Navigational device, invented to aid recovery of spacecraft from any orbit, also illustrates motions of satellites relative to earth and their entry-ranging requirements. Device rapidly and accurately defines lateral range requirements for spacecraft returning to any desired site without manual or computerized calculation of orbital equations of motion

Pritchard, E. B.

English

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Lateral-Ranqe 
Range Finder -	 Support Ring 
Figure 2. Operation of the Device 
B
Top View 
Front View 
December 1970	 Brief 70-10656 
NASA TECH BRIEF 
• -	
_•	
-_iiii________ 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the National Technical Information Service, Springfield, 
Virginia 22151. Requests for individual copies or questions relating to the Tech Brief progam may be directed to the Tech-
nology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Orbit, Reentry, and Landing Attachment for Globes 
A novel, simple, and inexpensive navigational de-
vice, invented to aid the recovery of spacecraft from 
any orbit, can be used to illustrate the motions of 
satellites relative to Earth, and the entry-ranging
1 and 2), a narrow strip made to fit snugly around the 
globe. Normal to the ring, another strip—the orbital 
track and longitudinal range finder—is passed around 
the globe and fixed to the ring at two diametrically 
opposed points, A and A , and the ends are joined by 
Lateral-Range 
Finder	 Detail A': Ring Joint 
Support 
^^ ^ital Ring
Support Ring
A' 
"^q Orbital Track 
and Longi-
tudinal-
Range Finder 
A' 
Lateral Range 
Finder
B 
•
B(/ I 
-r 
Orbital Track	 T 
"and Longitudinal-' 
Range Finder Side View 
Support Ring Figure 1. Views of the Device 
requirements of such vehicles. The device may be of 
interest to educators and to manufacturers of globes, 
maps, and graphic teaching aids. 
The attachment can be made wholly of 1/16-in. 
clear plastic. Its basic element is the support ring (Figs.
a press clip. At opposed points, B and B , midway be-
tween A and A , are pinned (single-pin joints) the 
ends of a semicircular strip that fits snugly around one-
half of the globe. This is the lateral range finder which, 
like the orbital track, is graduated in degrees. 
The attachment is placed on the globe such that the 
(continued overleaf) 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19700000636 2020-03-17T01:00:40+00:00Z
for all possible landing sites before lateral range 
requirements for the best group of sites could be 
defined.
	 4D 
Note: 
orbital track is at the desired inclination to the 
equator, with points A and A aligned with the orbital 
nodes for any particular point of initiation of the 
analysis. The orbital track thus lies over the point of 
entry, point C in Figure 2. The lateral range finder is 
then rotated on its pins until it lies over point-D, the 
desired landing point. Here it intersects the orbital 
track at point-E. Thus the longitudinal range can be 
read between C and E; the lateral range, between E 
and D. Subsequent orbital passes can be studied after 
appropriate shifts of the nodal line A—A' around the 
equator. 
The general purpose of this invention is to provide 
a rapid means of defining, with reasonable accuracy, 
the lateral range requirements for spacecraft returning 
from any orbit to any desired site. Lateral range re-
quirements, accurate within about 30 nautical miles, 
can be defined in less than 10 percent of the time re-
quired for calculation. Unattractive sites can be elimi-
nated visually without calculation. 
Prior methods required solving the orbital equations 
of motion either manually or by a computer program. 
The time-consuming procedure required calculations
No additional documentation is available. Specific 
questions-,however, may be directed to: 
Technology Utilization Officer 
Langley Research Center 
Hampton, Virginia 23365 
Reference: B70-10656 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to: 
Patent Counsel 
Mail Code 173 
Langley Research Center 
Langley Station 
Hampton, Va. 23365
Source: E. Brian Pritchard

Langley Research Center

(LAR- 10626)
ft 
Brief 70-10656	 Category 03


Orbit, reentry, and landing attachment for globes

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