ARCTUS
Encyclopedia
ARCTUS was a proposed design by Astrotech Corporation for a robotic spacecraft
that would deliver cargo to the International Space Station
. ARCTUS was planned to be launched by an Atlas V
rocket. Its pressurized cargo module would return to Earth and be recovered with a mid-air retrieval
operation.
Unpressurized Cargo Module (UCM): The UCM is located on the forward end of the vehicle and provides the means to carry the external cargo. The UCM can accommodate 3 metric tons or greater (subject to launch vehicle capability) of cargo (including Orbital Replacement Units for the ISS).
Pressurized Cargo Module (PCM): Built from two Centaur
aft bulkheads, the PCM can hold over 2 metric tons of internal cargo in its 18 cubic meter volume. Extended options are available providing upwards of 31 cubic meters, carrying more than 4 metric tons of pressurized cargo.
Service Module (SM): The SM is located on the aft end of vehicle and provides the interface with the launch vehicle, the Common Berthing Mechanism
(CBM) ISS interface, and the spacecraft Propulsion System.
Separation mechanisms are used to allow for separation of the UCM and SM prior to reentry of the PCM.
Avionics
The brain of ARCTUS is derived from the flight proven XSS-11 avionics and consists of a spacecraft computer, communications and power systems, guidance and navigation system, and associated software. The majority of the avionics will be housed inside the PCM to allow for recovery and reuse for future missions.
Propulsion System
A hydrazine monopropellant propulsion system provides full six degree of freedom control of ARCTUS. Eight propulsion tanks and thirty-two 9 pound rocket engine modules form the basis of the system.
Guidance, Navigation and Control
(GN&C)
The ARCTUS GN&C system is based on the XSS 11 avionics. The system consists of dual redundant Inertial Measurement Unit
s (IMUs) and Global Positioning System
(GPS) units, dual star trackers and associated flight software.
Payload Accommodations
The ARCTUS payload accommodations are based on SPACEHAB's 20 years of experience in delivering NASA
, ESA, JAXA, Russian
, and commercial cargo to space.
Environmental Control and Life Support System (ECLSS)
The ECLSS will maintain the pressurized environment (temperature and pressure) within the cargo requirements during all flight phases, as well crew requirements, while docked. The system will utilize SPACEHAB and ISS heritage hardware and a design similar to other ISS modules in order to minimize crew training and procedure development.
Reentry and Recovery System
After successful jettison of the UCM and SM, the PCM performs burns to reenter the Earth's atmosphere
with a trajectory targeting landing off the east coast of Florida
. The combination of a rigid, ablative nose cap and inflatable heat shield
will protect the vehicle during reentry heating. Upon successful reentry, a conventional drogue
and parafoil
system will slow the vehicle for recovery. A Mid Air Retrieval (MAR) operation will be used to minimize landing loads for the cargo.
Robotic spacecraft
A robotic spacecraft is a spacecraft with no humans on board, that is usually under telerobotic control. A robotic spacecraft designed to make scientific research measurements is often called a space probe. Many space missions are more suited to telerobotic rather than crewed operation, due to...
that would deliver cargo to the International Space Station
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
. ARCTUS was planned to be launched by an Atlas V
Atlas V
Atlas V is an active expendable launch system in the Atlas rocket family. Atlas V was formerly operated by Lockheed Martin, and is now operated by the Lockheed Martin-Boeing joint venture United Launch Alliance...
rocket. Its pressurized cargo module would return to Earth and be recovered with a mid-air retrieval
Mid-air retrieval
Mid-air retrieval is a technique used in atmospheric reentry when the reentering vehicle is incapable of a satisfactory unassisted landing. The vehicle is slowed by means of parachutes, and then a specially-equipped aircraft matches the vehicle's trajectory and catches it in mid-air.This is a risky...
operation.
Structures
ARCTUS will consist of three modules:Unpressurized Cargo Module (UCM): The UCM is located on the forward end of the vehicle and provides the means to carry the external cargo. The UCM can accommodate 3 metric tons or greater (subject to launch vehicle capability) of cargo (including Orbital Replacement Units for the ISS).
Pressurized Cargo Module (PCM): Built from two Centaur
Centaur (rocket stage)
Centaur is a rocket stage designed for use as the upper stage of space launch vehicles. Centaur boosts its satellite payload to geosynchronous orbit or, in the case of an interplanetary space probe, to or near to escape velocity...
aft bulkheads, the PCM can hold over 2 metric tons of internal cargo in its 18 cubic meter volume. Extended options are available providing upwards of 31 cubic meters, carrying more than 4 metric tons of pressurized cargo.
Service Module (SM): The SM is located on the aft end of vehicle and provides the interface with the launch vehicle, the Common Berthing Mechanism
Common Berthing Mechanism
The common berthing mechanism is a berthing mechanism used to connect all non-Russian pressurized modules of the International Space Station....
(CBM) ISS interface, and the spacecraft Propulsion System.
Separation mechanisms are used to allow for separation of the UCM and SM prior to reentry of the PCM.
Automated Rendezvous and Proximity Operations (ARPO) System
The ARPO system is designed to take the ARCTUS vehicle from the ISS stay-out zone (approximately 3 km radius) to the ISS capture box. ARCTUS will then be grappled by the Space Station Remote Manipulator System (SSRMS) and berthed on an ISS port (nominally ISS Harmony Nadir port).Avionics
Avionics
Avionics are electronic systems used on aircraft, artificial satellites and spacecraft.Avionic systems include communications, navigation, the display and management of multiple systems and the hundreds of systems that are fitted to aircraft to meet individual roles...
The brain of ARCTUS is derived from the flight proven XSS-11 avionics and consists of a spacecraft computer, communications and power systems, guidance and navigation system, and associated software. The majority of the avionics will be housed inside the PCM to allow for recovery and reuse for future missions.
Propulsion System
Spacecraft propulsion
Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellites. There are many different methods. Each method has drawbacks and advantages, and spacecraft propulsion is an active area of research. However, most spacecraft today are propelled by forcing a gas from the...
A hydrazine monopropellant propulsion system provides full six degree of freedom control of ARCTUS. Eight propulsion tanks and thirty-two 9 pound rocket engine modules form the basis of the system.
Guidance, Navigation and Control
Guidance, Navigation and Control
Guidance, navigation and control is a branch of engineering dealing with the design of systems to control the movement of vehicles, especially, automobiles, ships, aircraft, and spacecraft. In many cases these functions can be performed by trained humans...
(GN&C)
The ARCTUS GN&C system is based on the XSS 11 avionics. The system consists of dual redundant Inertial Measurement Unit
Inertial measurement unit
An inertial measurement unit, or IMU, is an electronic device that measures and reports on a craft's velocity, orientation, and gravitational forces, using a combination of accelerometers and gyroscopes. IMUs are typically used to maneuver aircraft, including UAVs, among many others, and...
s (IMUs) and Global Positioning System
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...
(GPS) units, dual star trackers and associated flight software.
Payload Accommodations
The ARCTUS payload accommodations are based on SPACEHAB's 20 years of experience in delivering NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
, ESA, JAXA, Russian
Russian Federal Space Agency
The Russian Federal Space Agency , commonly called Roscosmos and abbreviated as FKA and RKA , is the government agency responsible for the Russian space science program and general aerospace research. It was previously the Russian Aviation and Space Agency .Headquarters of Roscosmos are located...
, and commercial cargo to space.
Environmental Control and Life Support System (ECLSS)
The ECLSS will maintain the pressurized environment (temperature and pressure) within the cargo requirements during all flight phases, as well crew requirements, while docked. The system will utilize SPACEHAB and ISS heritage hardware and a design similar to other ISS modules in order to minimize crew training and procedure development.
Reentry and Recovery System
Reentry capsule
A reentry capsule is the portion of a spacecraft which returns to Earth following a space flight. The shape is determined partly by aerodynamics; a capsule is aerodynamically stable falling blunt end first, which allows only the blunt end to require a heat shield for atmospheric reentry. Its shape...
After successful jettison of the UCM and SM, the PCM performs burns to reenter the Earth's atmosphere
Earth's atmosphere
The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth's gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention , and reducing temperature extremes between day and night...
with a trajectory targeting landing off the east coast of Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. The combination of a rigid, ablative nose cap and inflatable heat shield
Heat shield
A heat shield is designed to shield a substance from absorbing excessive heat from an outside source by either dissipating, reflecting or simply absorbing the heat...
will protect the vehicle during reentry heating. Upon successful reentry, a conventional drogue
Drogue
A drogue is a device external to the boat, attached to the stern used to slow a boat down in a storm and to keep the hull perpendicular to the waves. The boat will not speed excessively down the slope of a wave and crash into the next one nor will it broach. By slowing the vessel in heavy...
and parafoil
Parafoil
A parafoil is a nonrigid airfoil with an aerodynamic cell structure which is inflated by the wind. Ram-air inflation forces the parafoil into a classic wing cross-section. Parafoils are most commonly constructed out of ripstop nylon....
system will slow the vehicle for recovery. A Mid Air Retrieval (MAR) operation will be used to minimize landing loads for the cargo.