Abstract:
A canisterized satellite dispenser includes one or more of: a pair of guide rails that eliminate the requirement of a rectangular profile for the satellite; a preload system that secures the canisterized satellite during transport and launch, and releases to deploy the canisterized satellite; a constant-force spring to provide a uniform and predictable dispensing force; an external rectangular profile in each dimension; and internal support surfaces that simplify the design of canisterized satellites, particularly those with deployable components. Each canisterized satellite includes a pair of opposing flanges on a lower portion of the satellite that ride in a channel formed by the dispenser&#39;s guide rails and restraining flanges; no other support constraints are imposed. During travel and launch, the satellite flanges are held against the restraining flanges, rigidly fixing the satellite to the dispenser until the satellite is deployed.

Description:
[0001]    This application claims the benefit of U.S. Provisional Patent Application 61/815,867, filed 25 Apr. 2013. 
     
    
       [0002]    This invention was made with U.S. Government support under SBIR Contract No. FA9453-11-C-0016 awarded by the U.S. Air Force, titled “Canisterized Satellite Development for Operational Responsive Space”. The U.S. Government has certain rights in the invention. 
     
    
     BACKGROUND AND SUMMARY OF THE INVENTION 
       [0003]    This invention relates to the field of satellites, and in particular to a dispenser for deploying canisterized satellites, such as CubeSat, from a larger spacecraft, such as a launch vehicle, a shuttle, or a space station. 
         [0004]    California Polytechnic State University (“Cal Poly”) initiated the CubeSat concept in 1999, to enable universities to perform space science and exploration. A basic CubeSat (“1U”) is a 10 cm 1  cube (one liter in volume) having a mass of not more than 1.33 kg. Other common sizes are available, including a “2U” that is 20 cm×10 cm×10 cm, and a “3U” that is 30 cm×10 cm×10 cm. Other sizes, such as a “6U” (30 cm×10 cm×20 cm), “12U” (30 cm×20 cm×20 cm), and “27U” (30 cm×30 cm×30 cm), have also been proposed.  1  Dimensions cited herein are ‘nominal’. 
         [0005]    In a typical university scenario, students build a CubeSat to perform a particular task in space, then coordinate with launch service providers to obtain “space-available” allocation on a delivery spacecraft, such as a launch vehicle, a shuttle, or a space station. Because the CubeSats are small, they may often be placed in the spaces between the larger payloads in the delivery spacecraft. 
         [0006]    To deploy a CubeSat in space, a dispensing device is used to ‘push’ the CubeSat away from the delivery spacecraft. This dispensing device is also used to transport the CubeSat and to secure it to the delivery spacecraft. Current dispensing devices include the “P-Pod” (Poly&#39;s Pico-satellite Orbital Deployer), designed by Cal Poly, and the ISIPOD deployer, designed by ISIS (Innovative Solutions In Space). The P-Pod deployer accommodates a “3U” CubeSat, or, equivalently, three “1U” CubeSats, or, one “1U” CubeSat and one “2U” CubeSat”. The ISIPOD is available in a variety of sizes. 
         [0007]      FIGS. 1A-1B  illustrate a conventional P-Pod device  100 . A spring-loaded door  110  secures the CubeSat(s) within the P-Pod. Upon receipt of a deployment signal, a release mechanism  120  releases the door  110 , which swings open at least 90 degrees. 
         [0008]    Within the P-Pod, a coil spring  160  is situated behind a push-plate  150 . As the CubeSats are inserted into the P-Pod, the coil spring  160  is compressed. After the CubeSats are inserted into the P-Pod, the door  110  is latched, holding the coil spring  160  in compression. Access doors  130  provide access to the inserted CubeSats, and may be used, for example, to charge batteries or run diagnostic tests. Mounting brackets  180  are used to secure the P-Pod to the delivery spacecraft. 
         [0009]    Release of the door  110  allows the coil spring  160  to push the push-plate  150  toward the door  110 , resulting in the discharge of the CubeSats from the P-Pod. Four teflon coated guide rails  170  are used to facilitate a lateral discharge of the CubeSats. Nominally, the CubeSats exit the P-Pod at about 1.6 m/sec; different sized coil springs  160  may be used to increase or decrease this exit velocity. Four spring plungers (not illustrated) in the rear of the P-Pod supplement the coil spring  160 . 
         [0010]      FIG. 2  illustrates a conventional “1U” CubeSat  200 . The “2U” and “3U” CubeSats have the same dimensions in the illustrated ‘x’ and ‘y’ directions, and extend further in the ‘z’ direction by a multiple of two and three, respectively. 
         [0011]    Each CubeSat, regardless of size, includes rails  270  that are configured to ride on the guide rails  170  of the P-Pod  100 . Spring plungers  220  are mounted on two of the rails  270 , and serve to separate the CubeSats during deployment when there are multiple CubeSats within the P-Pod. Switches  230  are mounted on the remaining two rails  270 , and serve to signal that the CubeSat has been deployed. 
         [0012]    The regions  210  between the rails  270  are illustrated as plane surfaces, but will typically include components of the CubeSat  200 , such as solar panels, deployable antennas, sensing instruments, and the like. The surfaces  210  merely identify the maximum extent that such components may occupy. Because the P-Pod  100  provides a sealed enclosure, the components of the CubeSat  200  need not be enclosed. Depending upon the arrangement of components within the CubeSat  200 , an access panel  240  may be provided on either or both sides of the CubeSat  200 , corresponding to the access panels  130  of the P-Pod  100 . 
         [0013]    The ISIPOD device includes features similar to the P-Pod  100 . 
         [0014]    Although the P-Pod and ISIPOD devices are relatively efficient and reliable, some of their features may be considered ‘sub-optimal’. 
         [0015]    For example, the requirement to provide four rails  270  on the CubeSat  200  requires the external profile of the CubeSat to be rectangular. Additionally, because the CubeSat  200  must ride the guide rails  170 , there must be a gap between the extent of the rails  270  of the CubeSat  200  and the distance between the guide rails  170  of the P-Pod. Although the gap may be slight (about 0.5 mm), it allows the CubeSat  200  to vibrate within the P-Pod  100  during transport and launch, which has damaging potential and is very difficult to analytically model. 
         [0016]    In like manner, because the guide rails  170  of the P-Pod  100  are the only surfaces that the CubeSat  200  may contact, and this contact must be via the rails  270  of the CubeSat  200 , the CubeSat  200  cannot rely on the P-Pod  100  for providing other support surfaces that might simplify the mechanical design of particular CubeSats  200 . 
         [0017]    The arrangement of the release mechanism  120  above the door  110  limits the options for mounting the P-Pod  100  in the delivery spacecraft, particularly when multiple P-Pods are included in the delivery spacecraft. 
         [0018]    The use of a coil spring  160  results in a non-uniform force being applied to the push-plate  150  as the spring  160  expands; it may also introduce an undesired torquing force, which could introduce a spin to the CubeSat as it is released. 
         [0019]    It would be advantageous to provide a canisterized satellite dispenser that overcomes one or more of the sub-optimal features of conventional canisterized satellite dispenser, such as P-Pod and ISIPOD. It would be advantageous to provide a canisterized satellite dispenser that has one or more of the following features: fewer than four guiderails, preloaded contact with the satellite, a rectangular profile in each dimension, a dispensing mechanism that does not use a coil spring, and an inner profile that allows further supporting contact with the canisterized satellite. 
         [0020]    These advantages, and others, can be realized by a canisterized satellite dispenser that includes one or more of: a pair of guide channels that eliminate the requirement of a rectangular profile for the satellite; a preload system that secures the canisterized satellite during transport and launch, and releases to dispense the canisterized satellite; a constant-force spring to provide a uniform and predictable dispensing force; an external rectangular profile in each dimension; and internal support surfaces that simplify the design of canisterized satellites, particularly those with deployable components. Each canisterized satellite includes a pair of opposing flanges on a lower portion of the satellite that ride in a channel formed by the dispenser&#39;s guide rails and restraining flanges; no other support constraints are imposed. During travel and launch, the satellite flanges are held against the restraining flanges, rigidly fixing the satellite to the dispenser until the satellite is deployed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The invention is explained in further detail, and by way of example, with reference to the accompanying drawings wherein: 
           [0022]      FIGS. 1A-1B  illustrate a conventional dispenser for CubeSats. 
           [0023]      FIG. 2  illustrates a conventional CubeSat payload. 
           [0024]      FIG. 3  illustrates an example dispenser in accordance with an aspect of this invention. 
           [0025]      FIG. 4  illustrates an example payload in accordance with an aspect of this invention. 
           [0026]      FIG. 5  illustrates example sizes of dispensers in accordance with an aspect of this invention. 
           [0027]      FIG. 6  illustrates an example combination of dispensers in accordance with an aspect of this invention. 
           [0028]      FIG. 7  illustrates example features for inclusion in dispensers in accordance with multiple aspects of this invention. 
           [0029]      FIGS. 8A-8D  illustrate an example preload system that secures an example payload to an example dispenser. 
           [0030]      FIGS. 9A-9D  illustrate an example latching system that secures a door of the dispenser. 
           [0031]      FIGS. 10A-10C  illustrate an example arrangement that dampens motion of the door as it opens, and prevents the door from bouncing back into the path of the payload. 
           [0032]      FIGS. 11A-11B  illustrate an example dispenser that dispenses payloads having deployable elements. 
           [0033]      FIGS. 12A-12C  illustrate the bounds associated with a payload, and example payloads having non-rectilinear shapes. 
           [0034]      FIGS. 13A-13B  illustrate an alternative preload system that secures an example payload to an example dispenser. 
       
    
    
       [0035]    Throughout the drawings, the same reference numerals indicate similar or corresponding features or functions. The drawings are included for illustrative purposes and are not intended to limit the scope of the invention. 
       DETAILED DESCRIPTION 
       [0036]    In the following description, for purposes of explanation rather than limitation, specific details are set forth such as the particular architecture, interfaces, techniques, etc., in order to provide a thorough understanding of the concepts of the invention. However, it will be apparent to those skilled in the art that the present invention may be practiced in other embodiments, which depart from these specific details. In like manner, the text of this description is directed to the example embodiments as illustrated in the Figures, and is not intended to limit the claimed invention beyond the limits expressly included in the claims. For purposes of simplicity and clarity, detailed descriptions of well-known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail. 
         [0037]    The invention is presented using an example set of different sized satellite dispensers with features associated with this invention. One of skill in the art will recognize that the features associated with this invention are substantially independent of the size or shape of the particular satellite dispenser. 
         [0038]      FIG. 3  illustrates an example dispenser  300  in accordance with an aspect of this invention, and  FIG. 4  illustrates a corresponding payload satellite  400 . In this example, the dispenser  300  is a “3U” configuration that, like the P-Pod  100  of  FIG. 1 , is able to accommodate three “1U” payloads, a “1U” payload and a “2U” payload, or a “3U” payload. The example payload  400  is a “3U” payload. 
         [0039]    As illustrated in  FIG. 3 , the example dispenser  300  includes guide rails  310  that guide the payload as it is dispensed (detailed below), and restraining flanges  320  that serve to restrain a payload  400  in transit and in flight. The payload  400  of  FIG. 4  illustrates a pair of flanges, or tabs  420  that are configured to lie under the pair of flanges  320  of the dispenser  300 , in the channels  330  formed by the guide rails  310  and the restraining flanges  320 . The flanges  420  of the payload  400  provide a slot  430  that accommodates the flange  320  of the dispenser  300 . A door, not illustrated, for the dispenser  300  is hinged at the lower portion of the dispenser  300 , and is arranged such that, when opened at 90 degrees, the surface of the door is below the height of the guide rails  310 , allowing the payload  400  to be deployed. The guide rails  310  may be configured to support the door. 
         [0040]    Because the payload  400  uses flanges  420  that travel atop the guide rails  310 , below the restraining flanges  320 , further attachment means are not required, and thus the dispenser  300  need not be further constrained to guide the payload  400  as it is being dispensed. This two-track constraint also allows the portion of the payload  400  above the flanges  420  to be arbitrarily shaped, eliminating the cubic profile requirement of CubeSat. The flat sidewalls  340  allow the payload  400  to use the sidewalls  340  for constraining deployable components of the payload  400 , as detailed further below. 
         [0041]    The rectangular exterior of the dispenser  300  and the siderails  350  allow the dispenser  300  to be mounted in the delivery vehicle in a variety of configurations, as illustrated further in  FIGS. 5 and 6 . 
         [0042]      FIG. 5  illustrates three example sizes of the dispenser. Dispenser  510  is a “three-unit” (“3U”) dispenser; dispenser  520  is a double-wide “6U” dispenser; and dispenser  530  is a double-wide and double-high “12U” dispenser. In this case, the designations “6U” and “12U” are volumetric designations. The “6U” dispenser  520  and “12U” dispenser  530  require each payload to be about twice the width of the standard payload of the “3U” dispenser  510 , while the “12U” dispenser  530  allows for payloads twice as tall as the standard payload of the “3U” and “6U” dispensers  510 ,  520 . 
         [0043]    Each of these dispensers include siderails  550  and rear support flange  560  that may be used to attach the dispenser to the delivery vehicle, to each other, to intermediate mounting plates, and so on. Access panels  540  on the sides of the payload and on the door enable access to the payload after it is loaded into the dispenser. Not illustrated, the rear section of the dispenser includes connectors/sockets for communications with the delivery vehicle, to communicate status and to receive deployment commands. Also, the door face of each dispenser may include provisions to mount to the delivery vehicle. 
         [0044]      FIG. 6  illustrates the mounting of thirty “3U” dispensers  510  on a conventional 41″ diameter mounting plate, commonly used for mounting elements to a launch vehicle. Structural integrity is enhanced by bolting adjacent dispensers  510  to each other using the side rails  550 . 
         [0045]      FIG. 7  illustrates example features for inclusion in dispensers in accordance with multiple aspects of this invention. For ease of reference, the initial digit in the reference numerals indicate which figure the feature is introduced; that is, for example, the elements  910 - 990  are detailed in the description of  FIG. 9 . 
         [0046]    Of particular note, the dispensers of this invention preferable use one or more constant-force springs  710 , such as a wound steel band. As contrast to the coil of the P-Pod, a constant-force spring  710  does not obey “Hooke&#39;s law”, which states that that the force provided by a compressed spring is proportion to the compressed distance. That is, in the P-Pod case, maximum force is exerted when the coiled spring is initially released, and this force decreases linearly as the coil expands to deploy the payload. 
         [0047]    In a wound steel band, similar to a tape-measure, the spring is relaxed when it is fully rolled up. As it is unrolled, the restoring force comes primarily from the portion of the ribbon near the roll. Because the geometry of that region remains nearly constant as the spring unrolls, the resulting force is substantially constant. 
         [0048]    Although a wound band is illustrated in  FIG. 7 , a conical spring can be situated in the rear of the dispenser, similar to the coil spring of P-Pod, but having a variable pitch. Putting a larger pitch in the larger coils and a smaller pitch in the smaller coils of the conical spring will force the spring to expand all the coils at the same rate when released. However, a conical spring, like the coil spring of P-Pod, may introduce an undesirable torque as it unwinds. Further, clock springs, connected to the ejection plate via cables may be used in place of the constant force spring. 
         [0049]    The constant-force spring  710  is coupled to a push-plate guide  720  that rides on a rail  730 . The guide  720  is attached to a push-plate (not illustrated) that is pushed to the rear of the dispenser as the payload is inserted, extending the steel band of the spring  710 . During deployment, the push-plate urges the payload out the door (not illustrated) as the push-plate guide  720  is retracted by the spring  710 . As noted above ( FIGS. 3 and 4 ), the payload is guided via the travel of the flange  420  within the channel formed by the rail  310  and flange  320 . 
         [0050]    In accordance with another aspect of this invention, the flanges  320  and  420  may be used to secure the payload to the dispenser until it is deployed. 
         [0051]      FIGS. 8A-8D  illustrate an example preload system that secures the payload to an example dispenser. A preload bar  820  and flexure element  810  are situated in the space below the flange  320  in the dispenser, as illustrated in  FIG. 8D , with a gap  327  below the flange  320  sufficient to accommodate the flange  420  of the payload. 
         [0052]      FIG. 8A  illustrates a lateral view of the region below the flange  320  when the preload bar  820  is in the release state, when the door  850  is open, for loading and deploying the payload. As illustrated, in this state, there is a gap  828  between the flange  320  on the dispenser and flange  420  on the payload; this gap allows the payload to freely travel below the flange  320 . 
         [0053]    The preload bar  820  is situated upon a flexure element  810  that includes sloped flexure members  815 . These members  815  are substantially rigid, but are shaped to allow some bending under pressure, to accommodate slight variations in the thickness of flange  420 . In the release state, the preload bar  820  will contact the members  815  at some point, designated  816  in  FIG. 8A , on the sloped portion of each member  815 . This point  816  is determined by the lateral location of the preload bar  820  when the door  850  is open. As detailed further below, springs  870 ,  875  ( FIG. 8C ) at the rear of the dispenser urge the preload bar  820  toward the door, as does the slope of the flexure members  815 . The point  816  on the flexure member  815  should be situated such that the aforementioned gap  828  is available when the payload flange  420  is situated below the dispenser flange  320 . 
         [0054]    The door  850  includes a cam  860  that is in contact with a roller  840  on the preload bar  820 . As the door  850  is closed, the cam  860  urges the preload bar  820  toward the rear of the dispenser. As the preload bar  820  travels toward the rear, the sloped flexure members  815  cause the preload bar  820  to rise, reducing the gap  828  between the payload flange  420  and the dispenser flange  320 . 
         [0055]      FIG. 8B  illustrates the secured state, when the door  850  is closed. As illustrated, the preload bar  820  has been moved to point  817  on the flexure member  815 , farther up the member  815  than the point  816  of the released state. In the secured state, the gap  828  between the flanges  420 ,  320  is eliminated, and the payload flange  420  is secured against the dispenser flange  320  by the upward force exerted on the preload bar  820  by the flexure members  815 . 
         [0056]    As noted above,  FIG. 8C  illustrates two springs  870  and  875  that urge the preload bar  820  toward the door. Spring  870  is a high force spring (˜20 lbf) with a short travel that is used to overcome bearing stiction, whereas spring  875  is a low force spring (˜10 lbf) with a longer travel that is used to keep the door open and the flexure members  815  unloaded, and to prevent payload seizure. 
         [0057]    Of particular note, the preload system operates in a bistable manner (released and secured states), such that no external force is required to maintain the system in either state. When the door  850  is open, the configuration of the roller  840  and the cam  860  prevents the door  850  from swinging closed, keeping the preload system in the released state. To transition to the secured state, an external force is required to rotate the door  850 . As detailed below, a latching system secures the door  850  in the closed position of  FIG. 8B , and the external force can be removed. When the door latch is released, the movement of the preload bar  820  urges the door outward, and the configuration of the roller  840  and the cam  860  forces the door to continue to the fully open position of  FIG. 8A . 
         [0058]    Also of note, the opened state maintains the door at 90°, allowing the payload to be ejected without interference, and also allowing dispensers to be positioned adjacent each other without one dispenser&#39;s door interfering with the ejection of payloads from other dispensers. 
         [0059]      FIGS. 9A-9D  illustrate the operation of the example latching system that secures the door of the dispenser. As illustrated in  FIG. 9A , the latching system includes a latch  910  that catches a latch element  990  that is situated on the upper portion of the door  850  (partially illustrated by dotted lines), opposite the hinged portion of the door  850 . The latch element  990  may, for example, be a bearing, a tab, a rod, a shaft, and so on. When secured in the latch  910 , the latch element  990  cannot move, holding the door  850  shut. This latch and latch element arrangement is commonly used in automobile trunks and engine hoods. 
         [0060]    In this example, a motor  960  rotates a cam  950  about a bearing  955 . To unlatch the door, the rotation of the cam  950  urges an actuator rod  940  toward the door, and this lateral movement of the rod  940  causes a rotation of a latch lock  920  about a bearing  925 , which causes the latch  910  to be released, as detailed in  FIGS. 9B-9D . A torsion spring  970  is coupled to the rod  940  and holds the rod  940  against the cam  950 , so that shock and vibrations will not cause an accidental release of the latch  910 . 
         [0061]      FIG. 9B  illustrates the configuration of the latch  910  and the latch lock  920  while the door is in the latched state. The latch  910  includes a hook-like feature  919  that serves to engage the latch element  990 , preventing an outward (upward in  FIG. 9B ) movement of the latch element  990 , securing the door in a closed position. 
         [0062]    The latch  910  includes a surface  918  and latch lock  920  includes a feature  928  that rests against this surface  918 , maintaining the latch in the latched state without external forces being applied. A stop element  980  prevents a further clockwise rotation of the latch lock  920  in the latched state. A spring  930  urges the lower portions of the latch  910  and latch lock  920  together, holding the feature  928  in the latch lock  920  against the surface  918 , preventing the rotation of the latch  910 . 
         [0063]      FIG. 9C  illustrates a transition from the latched state to the released state, in response to the lateral movement of the actuator rod  940 . As the rod  940  moves toward the door (upward in  FIGS. 9B-9D ), it forces the latch lock  920  to rotate (counterclockwise in  FIG. 9B ). This rotation causes the feature  928  to move off the surface  918  of the latch  910 . Once released, the spring  930  pulls the latch  910  in a counterclockwise direction about bearing  915 , urging the feature  919  away from the latch element  990 . 
         [0064]      FIG. 9D  illustrates the configuration of the latch  910  and latch lock  920  when the latching system is in the released state. The continued counterclockwise rotation of the latch  910  results in the release of the latch element  990  from the feature  919  of the latch  910 . Once released, the door swings open due to the lateral force of the preload bar  820  against the cam  860  of the door  850  ( FIG. 8B ). In this state, the spring  930  serves to hold the latch  910  in the open state, while the continued rotation of the cam  950  ( FIG. 9A ) returns the actuator rod  940  to its original lateral position of  FIG. 9B . 
         [0065]    The closing of the door causes the latching system to re-enter the latched state of  FIG. 9B . As the door is closed, the latch element  990  strikes the latch  910  at the surface  917 , which causes a clockwise rotation of the latch  910 . Continued closing pressure continues to rotate the latch  910  such that the latch feature  919  captures the latch element  990 . The spring  930  urges the lower portions of the latch lock  920  and latch  910  together, causing the feature  928  on the latch lock to be positioned on the surface  918  on the latch  910 , locking the latch in the closed state of  FIG. 9B . 
         [0066]    As with the preload system, the illustrated latching system operates in a bistable manner, such that in each state, the latched state and the released state, the system will remain in that state unless and until another force is applied. Accordingly, no external force is required to maintain the latching system in each state. In  FIG. 9B , the latched state, the feature  928  being situated upon the surface  918  keeps the latch from rotating until the actuator rod  940  applies the force to initiate the change of state to the released state. In  FIG. 9C , the spring  930  prevents the rotation of the latch until the door latch element  990  applies the force to initiate the change to the latched state. 
         [0067]    It is significant to note that in this example dispenser, the closing of the door effects both a securing of the payload in the dispenser, as well as the ‘automatic’ latching of the door. 
         [0068]      FIGS. 10A-10C  illustrate an example arrangement that dampens motion of the door as it opens, and prevents the door from bouncing back into the path of the payload. 
         [0069]      FIG. 10A  illustrates a portion of a dispenser  300  with the door  850  in a latched position. The door  850  is configured to pivot about an axis  1080  upon release, and includes a dampening/securing element  1010  with a flange  1020  that serves to dampen motion of the door as it opens, and prevent the door from bouncing back into the path of the payload. The dispenser  300  is illustrated with a lower exterior surface  1030 , which may be the lower extreme of the dispenser  300 , or a formed surface above the lower extreme of the dispenser  300 . 
         [0070]      FIG. 10B  illustrates the dispenser  300  upon release of the door  850 . The door  850  pivots about the axis  1080 , and the flange  1020  comes in contact with the edge of the surface  1030 . The tensile strength of the flange  1020  introduces a resistance to the motion of the door  850 , dampening this motion. 
         [0071]    As the door  850  continues to open, being pushed by the preload bar  820  ( FIGS. 8A-8D ), and the payload being urged out the door by the push-plate (not illustrated) of the dispenser  300 , the flange  1020  flexes and continues to resist the clockwise motion of the door. At some point of maximum resistance, the gradient of the force exerted by the flange  1020  reverses, and the flexing of the flange  1020  contributes to the clockwise rotation of the door  850 . 
         [0072]      FIG. 10C  illustrates the door  850  when it is fully opened. In this state, the flange  1020  serves to resist a counterclockwise rotation of the door  850 , preventing the door  850  from bouncing back into the path of the payload being ejected (not illustrated). As in a number of features detailed above, the dampening structure  1010 - 1020  maintains the state illustrated in  FIG. 10C  without the need for external forces to be applied. 
         [0073]    As noted above with respect to  FIG. 3 , an aspect of this invention is the use of flat surfaces on the walls  340  of the dispenser  300  to facilitate payloads having deployable components, such as antennas and solar panels. One of skill in the art will recognize that such flat surfaces may be provided on the ‘floor’ and ‘ceiling’ of the dispenser as well. In an example embodiment, these flat surfaces are situated slightly beyond the horizontal and vertical extents of the specified payload dimensions, and the door opening is configured to be at least as high and wide as the distance between these flat surfaces, presenting a unobstructed path for payload that rely on these surfaces. 
         [0074]      FIGS. 11A-11B  illustrate an example dispenser that dispenses payloads having deployable elements. The payload  1100  includes one or more components  1110  that are intended to be separated/deployed at least in part from the major body  1120  of the payload  1100 . Typically, these components are spring-loaded for release after deployment. In a conventional payload dispenser, such as P-Pod, the payload must include the ability to restrain the deployable components  1110  while it is in the P-Pod dispenser, and include one or more sensors that detect the ejection of the payload  1100  before deploying the components  1110 . 
         [0075]    In accordance with another aspect of this invention, the smooth walls  1150  allow the payload  1100  to use these walls to support the use of deployable elements  1110  in payloads  1100 . In this example embodiment, wheels, or rollers  1130  are included on the deployable component  1110  to minimize the friction as the component  1110  is rolled along the wall or ceiling smooth surface  1150  of the dispenser  300 . 
         [0076]    As the payload  1100  is ejected from the dispenser  300 , the rollers  1130  roll along the smooth surface  1150  until the payload exits the dispenser  300 . As illustrated in  FIG. 11B , due to the spring loading of the components  1110  relative to the major body  1120  of the payload  1100 , when the payload  1100  is ejected from the dispenser  300 , the deployable components  1110  are deployed from the payload main body  1120 . 
         [0077]    The payload  400  of  FIG. 4  appears as a solid block, and, in the P-Pod scenario, must be of rectangular shape to support the 4-sided guide rail  270  requirement of P-Pod and CubeSat. However, in accordance with another aspect of this invention, the payload  400  need not have a cubic or rectilinear profile. 
         [0078]      FIGS. 12A-12C  illustrate the bounds associated with an example payload, and example payloads having non-rectilinear shapes. 
         [0079]    Because the mounting, launching, and ejection of the payload  400  only requires that the payload  400  include flanges  420  that are spaced a certain distance apart ( FIGS. 3-4 ), the remainder of the volume within the regions identified by the extent lines  1210 ,  1220 , and  1230  may be available for as much or as little actual volume of the particular payload  400  within these extent bounds, as illustrated in  FIG. 12A . 
         [0080]    Consequently, as illustrated in  FIGS. 12B and 12C , the deployable payloads of this invention may include relatively arbitrary profiles and configurations. 
         [0081]    As illustrated in  FIG. 12B , the payload  1250  is octagonal shaped, yet includes the flanges  420  required for a proper payload for the disclosed preferred embodiments provided the payload  1250  does not extend beyond the aforementioned bounds of the payload. 
         [0082]    The payload need not occupy all, or even most of the volume of the available space, and in some embodiments may be substantially smaller than the available space, as illustrated in  FIG. 12C . In such cases, the payload  1260  preferably includes ‘skids’/flanges  420  that guide the payload through the channels of the dispenser  300 . 
         [0083]    The foregoing merely illustrates the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are thus within its spirit and scope. For example,  FIGS. 13A-13B  illustrate an alternative preload arrangement. In this arrangement, a single flexure element  810 ′, which is fixedly attached to the floor of the canister (not shown), incorporates the functions of the flexure element  810  and the preload bar  820  of  FIGS. 8A-8B . That is, the flexure element  810 ′ includes flexure members  815 ′ and a central preload bar  820 ′. When the door is open ( FIG. 13A ), the flexure members  815 ′ are in a relaxed state, and a gap  828  exists between the payload flange  420  and the dispenser flange  320 , allowing the payload to be inserted or ejected. When the door is closed, the element  860 ′, which may be a screw or a bearing, acts as a cam and exerts a lateral force on the preload bar  820 ′ of the flexure element  810 ′, which consequently exerts an upward and downward force of the upper and lower flexure members  815 ′, respectively. This force causes the flexure element  810  to lift the payload, via the payload flange  420 , eliminating the gap  828 , and clamping the payload flange  420  to the canister flange  320 . This clamping force is maintained until the door is re-opened, allowing the payload to be ejected. These and other system configuration and optimization features will be evident to one of ordinary skill in the art in view of this disclosure, and are included within the scope of the following claims. 
         [0084]    In interpreting these claims, it should be understood that: 
         [0085]    a) the word “comprising” does not exclude the presence of other elements or acts than those listed in a given claim; 
         [0086]    b) the word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements; 
         [0087]    c) any reference signs in the claims do not limit their scope; 
         [0088]    d) several “means” may be represented by the same item or hardware or software implemented structure or function; 
         [0089]    e) each of the disclosed elements may be comprised of a combination of hardware portions (e.g., including discrete and integrated electronic circuitry) and software portions (e.g., computer programming). 
         [0090]    f) hardware portions may include a processor, and software portions may be stored on a non-transitory computer-readable medium, and may be configured to cause the processor to perform some or all of the functions of one or more of the disclosed elements; 
         [0091]    g) hardware portions may be comprised of one or both of analog and digital portions; 
         [0092]    h) any of the disclosed devices or portions thereof may be combined together or separated into further portions unless specifically stated otherwise; 
         [0093]    i) no specific sequence of acts is intended to be required unless specifically indicated; and 
         [0094]    j) the term “plurality of” an element includes two or more of the claimed element, and does not imply any particular range of number of elements; that is, a plurality of elements can be as few as two elements, and can include an immeasurable number of elements.