Development and characteristics of docking structure and apparatus for spacecraft dockin

Blumrich, J. F.

English

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NATIONAL AERONAUTICS AND SPACE ADMINISTRATION 
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MORANDUM 
,#TO : KSI/Scientif i c  & Technical Information Division 
A t t n :  M i s s  Winnie M. Morgan 
FROM : GP/Office of Ass is tan t  General 
# Counsel for  Patent  Matters 
SUBJECT: Announcement of NASA-Owned 
U.S. Patents  i n  STAR 
I n  accordance with t h e  procedures contained i n  t h e  Code GP 
t o  Code USI memorandum on t h i s  subjec t ,  dated June 8, 1970, 
t h e  at tached NASA-owned U,S. pa ten t  is  being forwarded f o r  
abs t r ac t ing  and announcement i n  NASA STAR. 
The following information is  provided: 
U.S. Pa ten t  N o ,  
Corporate Source 
Supplementary 
Corporate Source 
NASA Patent C a s e  No.: 
Gayle Parker 
Enclosure : 
Copy of Patent  
https://ntrs.nasa.gov/search.jsp?R=19710014436 2020-03-17T03:04:40+00:00Z
Filed July 13, 15367 
DOCKING STRUCTURE FOR SPACECRAFT 
Sheet 1 of  2 
n 
OSEF F BLUMRICH 
ROMDAL G. CRAWFOR 
J. F. BLUMRICH ETAL 
DOCKING STRUCTURE FOR SPACECRAFT 
Filed July 13, 1567 Sheet 2 of  2 
45 
43 
4 
4 
FIG. 4 
JOSEF F. BLUMRICH 
RONDAL G. CRAWFORD 
IPIVEW TOR. (SI 
BY 
3,443,773 
Ser. No. 653,277 
~~ 
A CT 
A docking structure for a pair of spacecraft with the 
docking end of the first spacecraft having a circular open- 
ing that receives a projecting incoming element on the 
docking end of the second spacecraft. At the free end 
qf the incoming element is the apex of a pyramid struc- 
ture that diverges toward the second spacecraft and 
merges into a prismatic portion that is relatively shorter 
than the pyramid structure and is connected to the second 
spacecraft. The side of the circular opening in the first 
spacecraft initially contacts one or more corners of the 
pyramid portion of the incoming projecting element and 
subsequently guides the incoming element into the 
docked position wherein the side of the circular opening 
engages the corners of the prismatic portion of the in- 
coming element. Energy absorbing crushable material 
pads are provided between the mating surfaces of the first 
and second spacecraft and automatic latching means are 
provided for locking the projecting elements within the 
circular openings. 
The invention described herein was made by employees 
of the United States Government and may be manu- 
factured and used by or for the Government for govern- 
mental purposes without the payment of any royalties 
thereon or therefor. 
Background of the invention 
This invention relates generally to docking structures 
and more particularly to means for docking spacecraft 
while such craft are in flight, 
Rendezvousing and docking of space vehicles consti- 
tutes an essential and critical operation in future space 
exploration since, in making trips to the moon and planets, 
it  is required that crew members, fuel and other supplies 
be transferred from one vehicle to the other during flight. 
As is always the case with flight hardware, it is desirable 
that the docking structure be of the least possible weight 
while affording maximum reliability. A principal disad- 
vantage of existing docking structures is the relatively 
large amount of weight and length or height required for 
their construction, particularly when applied to large- 
diameter space vehicles. 
Docking structures which have been used or proposed 
heretofore typically comprise a female cone or conical 
frustrum on one spacecraft that receives a corresponding 
male cone or conical frustrum on the other spacecraft. In 
this kind of arrangement the apex or tip of the cone or 
the rim of the conical frustrum initially contacts the in- 
side of the female conical receptacle and subsequently 
slides into final position thus requiring that the receptacle 
Gone be designed to accept concentrated loads at any 
point on its surface. This necessitates that the receptacle 
cone be relatively heavy and also that the supporting 
frame members that transfer the loads from the recep- 
tacle to the primary structure of the space vehicle be 
relatively heavy. Moreover, the length or height of pre- 
vious docking structures contributes unduly to the l e n d  
of the space vehicles in which they are incorporated. 
Thus, a reduction in length of the docking structure wodd 
also reduce the overall length of the space vehicles. 
Srrmmary of the invention 
The invention comprises cooperating structures on first 
and second space vehicles to be docked in flight. A cir- 
cular opening having a relatively narrow sidewall is 
provided at the docking end of the first vehicle while 
the second vehicle is equipped with a projecting docking 
element with the free end thereof constituting the apex of 
a pyramid. The pyramid structure diverges from the 
apex toward the body of the second vehicle and then 
merges into a prismatic portion that is normally shorter 
than the pyramid structure and is firmly connected to the 
15 second vehicle. During the docking operation the apex Of 
the pyramid portion of the docking element enters the 
circular opening in the first vehicle and one or more of 
the oorners of the pyramid portion initially contacts the 
sidewall of the circular opening. Subsequently the project- 
20 ing docking element is guided into and centered within 
the circular opening while the sidewall of the circular 
opening moves over the pyramid portion and ultimately 
engages all corners of the prismatic portion the sides of 
which are of a width substantially equal to a chord of 
25 the circle defined by the circular opening. Automatic 
latching means are provided for locking the projecting 
docking element within the circular opening, and energy 
absorbing means ace provided between the mating sur- 
faces of the first and second vehicles to absorb the dock- 
Accordingly, it is a general object of the present in- 
vention to provide an improved docking structure particu- 
larly from the standpoint of weight saving. 
Another object of the invention is to provide a docking 
35 structure that automatically guides the docking vehicles 
into proper alignment and couples the vehicles together 
with the use of structure reduced substantially both in 
bulk and weight. 
Another object of the invention is to provide a docking 
40 structure that can be applied to large diameter space ve- 
hicles for successfully docking such vehicles while still 
using docking structure of relatively small dimension and 
weight. 
These and ,other objects and advantages of the inven- 
45 tion will become apparent upon reference to the following 
specification, attendant claims and drawings. 
Brief description of the drcrwing 
30 ingenergy. 
FIGURE 1 is a view showing two space vehicles 
FIGURE 2 is a view, partially broken away, showing 
the docking ends of the space vehicles of FIGURE 1 
subsequent to the docking maneuver; 
FIGURE 3 is an enlarged elevational view of a pro- 
55 jecting docking element on one vehicle that enters a cu- 
cular opening in the opposite vehicle during the docking 
operation; 
FIGURE 4 is a schematic perspective view indicating 
6o the framing arrangement of the docking element shown 
in FIGURE 3; 
FIGURE 5 is a cross sectional view taken along line 
50 odented for docking; 
5-5 of FIGURE 2. 
Description of the preferred embodiment 
Referring to FIGURE 1 therein is shown space ve- 
hicles If and 13 oriented for docking while in flight so 
that operations such as transfer of fuel, supplies or crew 
members may be accomplished from one vehicle to the 
70 other, the vehicle B3 being provided with a rocket engine 
15 and the vehicle 11 being provided with a plurality of 
rocket engines 17. The vehicle 13 is equipped with two 
65 
3,443,773 
diametrically opposed dock elements 19 that are about 
to project into circular openings 21 (FIGURES 2 and 5 )  
at the docking end of vehicle 11. 
recess 23 in forming the circular opening 21. It is noted 
that the framing structure that defines the opening 21 
is relatively short dimension in cross-section thickness and 
width and constitutes essentially a light weight ring. To  
support the member 27 very jirmly, a strut 3 
between the member 27 and an annular frame member 33 
of the vehicle 11, it being understood that several such 
struts could be provided if deemed necessary. 
As shown in FiIGURES 3 and 4, the projecting docking 
element 19'is an open frame structure comprising a pyra- 
mid portion 35 and a prismatic portion 37. The pyramid 
portion 35 includes four primary frame members 39, one 
at each corner thereof, with these members converging at 
an apex where they are joined as by welding to plate 41. 
As will be explained hereafter, at least one of the mem- 
bers 39 is releasably connected to the plate 41 for pur- 
poses to be set forth. 
Each of the frame members 39 is braced by perpendicu- 
larly related braces 42 connected to and extending be- 
tween diametrically opposed members 39. At the junction 
between the pyramid portion 35 and the prismatic portion 
37 intermediate braces 43 span all four sides of the pyra- 
mid base. The prismatic portion 37 is formed by four 
parallel primary frame members 45 matching end to end 
with the members 39 and being braced at their other ends 
by braces 47 about all four sides of the prismatic portion 
37. The prismatic portion 37 is further ,braced by diagonal 
braces 49 extending between upper and lower corners of 
the prismatic portion, and diagonal braces 51 and 52 ex- 
tending between two comers of the prismatic portion at 
opposite ends thereof. All of the frame members, with 
the exception of the end braces 47, comprise two angle 
members joined together to form a T-shaped cross sec- 
tion and the end braces 47 are single angle members, it 
being obvious that other shaped frame members may be 
employed. 
At one corner of the prismatic portion 37 a latch 53 
is pivotally mounted at 55 to the stem of the T-shaped 
member 45. The latch 53 is of a bell crank configuration 
including a handle 57 connected to a spring 59 also con- 
nected through an aperture (not shown) in the end brace 
52 to bias the latch 53 in the latching position. A slot 63 
is provided in the flange of the frame member 45 to per- 
mit the latch to swing between latching and unlatching 
positions. As the docking operation occurs the members 
27 and 25 that form the circular opening 21 will engage 
the corners of the prismatic portion 37 as the projecting 
element 19 moves into the opening 21 and the latch 53 
will be pressed inwardly by the sidewall of opening 21 
and after the latch has passed the sidewall of opening 21 
it will be returned to its latching position under force of 
spring 59. A surface 65 is formed on the frame member 
27 to fit against an edge surface 67 of the latch 53. 
To facilitate the transfer of crew members or s u p  
plies through the docking structure, one or more of the 
primary frame members 39 of the pyramid portion 35 
may be adapted for being disconnected at the apex of the 
pyramid portion and pivoted outwardly to open up a bet- 
ter passageway between the docked vehicles. In FIGURE 
3 one of the frame members 39 has it 
notched at one end at 49 and the connect 
recessed at 71 to receive an overlapping 
and a manually operated quick-disconnect 
bolt portion that extends through the re- 
1 and into a slot 76 in the 
bayonet type catch on its 
end that rotate8 90 degrees or more in the slot 7 
lease the member 39 fro e plate 41. The end of the 
member 39 opposite the latch 75 has its flanges notched 
at 77 so that the end portion of member 39 fits between a 
pair of projecting plates 79 welded on each side of the 
corresponding frame member 45. The web portion at the 
end of the frame member 45 is angled slightly at 81 so 
that the member 39 may pivot outwardly around a pivot 
83 extending through the plates 79 and the member 39. 
The projecting docking elements 19 are mounted on 
the docking end of the vehicle 13 within a square frame 
85 (see FIGURES 2 and 3 ) .  The kame structure 85 is 
well supported by struts 87 extending from the frame 
structure 85 to an annular frame member 89 of the space 
vehicle 113. At the corners of the frame 85 slots 91 are 
15 incorporated that receive mounting plates 93 welded to 
the respective corners at the end of the prismatic portion 
37 of the docking element 19. 
Since the projecting docking element 19 may be re- 
quired to absorb substantial lateral impact loads that will 
20 occur at the first contact between the pyramid portion 35 
and the sidewall of the circular opening 21, shock absorb- 
ing elements are built into the mounting between the 
docking element 19 and the vehicle 13. Thus, a yieldable 
material such as crushable honeycomb material 95 (FIG- 
25 URE 3 )  is disposed in the slots 91. It is not intended that 
the crushable material 95 absorb the docking energy but 
only the lateral impact forces applied to the docking ele- 
ment 35 when making initial contact with the sidewall 
of the circular opening 21. 
When docking occurs between the vehicles 11 and 13 
the apex of the pyramid portion 35 of each docking ele- 
ment 19 enters the corresponding circular opening 21, 
and one or more of the primary frame members 39 of 
each docking element initially contacts the sidewalls of 
35 the respective openings 21. Subsequently, the docking 
elements 19 are guided into and centered within the open- 
ings 21 while the sidewalls of the openings move over the 
pyramid portion 35 and ultimately engage all four corners 
of the prismatic portions 37 the sides of which are sub- 
40 stantially equal to a chord of the circles defined by the 
openings 21 (see FIGURE 5). The latch 53 on each 
docking element locks the docking elements 19 within the 
openings 21 in the manner previously described. 
The docking energy is absorbed by a plurality of pads 
45 97 (FIGURE 5) of crushable material, for example, 
crushable metallic honeycomb, attached to and radially 
spaced around the annular frame member 25 of the space 
vehicle 11. The height of the prismatic portion 37 of the 
projecting docking element 19 should be greater than the 
50 thickness of the pads 97 so that absorption of the dock- 
ing energy will begin only after the sidewalls of the circu- 
lar openings 21 have encircled the prismatic portion of the 
projecting docking elements 19. 
When it is desired to separate the vehicles 11 and 13 
55 such separation may be accomplished by one of the exist- 
ing methods, such as the shaped charged method, along a 
separation plane 99 which would leave the terminal outer 
shell or skirt of the vehicle 13, including 
ture of vehicle 13, attached to the vehicl 
60 the vehicle 13 of this weight and giving it this advantage 
in completing its mission after leaving the spacecraft 11. 
It is evident that the vehicles may also be separated along 
their original meeting line leaving both vehicles intact with 
the latches 53 being withdrawn by any means desired. 
From the foregoing it can be seen that the invention 
provides a simple and very light weight docking structure 
while affording a reliable means of $ringing the space- 
craft into proper docking alignment and of adequately 
a. absorbing the docking energy. The heavy and bulky struc- 
ture of previous docking devices has been largely elimi- 
nated and no reliability has been sacrificed. 
Obviously, many modifications and variations of the 
present invention are possible in the light Qf the abovg 
30 
65 
75 teachings. 
3,443,773 
We claim: 
1. A spacecraft having a docking structure at the dock- 
(a) a docking element projecting from said docking end 
(b) said docking element comprising a pyramid por- 
(c) the projecting end of said docking element consti- 
(d) the other end of said docking element constituting 1o 
(e) said other end being anchored to said docking end 
(f) said pyramid portion and said prismatic portion 
(d) the other end of said docking element constituting 
one end of said prismatic portion; 
(e) said other end being anchored to said docking end 
of said one spacecraft; 
( f )  the docking end of the other of said pair of space- 
craft having an opening therein adapted to receive 
said docking element of said one spacecraft; 
(g) said opening having a circular entrance adapted to 
guide said docking element into said opening; 
(h) the sides of said prismatic portion ,being substan- 
tially equal in width to a chord of the circle defined 
by said circular entrance whereby the comers of said 
prismatic portion when entering said entrance will 
bear on the sidewall of said entrance and stabilize 
said projecting element. 
7. The invention as defined in claim 6 wherein said 
2. The invention as defined in claim 1 wherein said circular entrance comprises a circular frame having a 
docking element comprises an open frame structure having cross section less in thickness and width than the length 
a primary frame member extending longitudinally of the of said prismatic portion. 
docking element at each corner of said pyramid portion 20 8. The invention as defined in claim 6 wherein said 
and said prismatic portion. docking structure on one of said pair of spacecraft incor- 
3. The invention as defined in claim 2 wherein said porates means for latching said docking element within 
pyramid portion is longer than said prismatic portion. said opening. 
4. The invention as defined in claim 1 wherein said 9. The invention as defined in claim 6 including energy 
docking element includes quick-disconnect means for per- 25 absorbing means carried by the docking end of one of said 
mitthg displacement of the structure of said docking ele- Pair of spacecraft. 
ment to facilitate a passageway through said docking IO. The invention as defined in claim 6 wherein said 
element. anchoring between said other end of said docking element 
5. The invention as defined in claim 1 wherein said and said docking end of said one spacecraft includes yield- 
pyramid portion has four faces and said prismatic portion 30 able shock absorbing means for absorbing lateral impact 
has four sides, said faces corresponding to said sides at the loads that Occur at the first contact between the pyramid 
junction between said pyramid portion and said prismatic Portion of said docking element and said sidewall of said 
portion. circular opening. 
6. Docking structure for in flight docking of a pair of eferences Cited 
UNITED STATES PATENTS (a) a docking element projecting from the docking end 
of one of said spacecraft; 3,201,065 811965 Dunn -- -----__-______ 244-1 
(b) said docking element comprising a pyramid portion 3,254,863 611966 Tyler _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _  244-1 
and a prismatic portion; 3,391,881 711968 Maltby -______-_______ 244-1 
(c) the projecting end of said docking element consti- 40 
tuthg the apex of said pyramid portion; 
ing end thereof, said docking structure comprising: 
of said spacecraft; 
tion and a prismatic portion; 
tuting the apex of said pyramid portion; 
one end of said prismatic portion; 
of said spacecraft; 
being joined between said ends of said docking ele- 15 
ment. 
spacecraft comprising: 35 
FERGUS S .  MIDDLETON, Primmy Examiner. 


Docking structure for spacecraft Patent

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