FRIEDMAN, Chief Judge,
delivered the opinion of the court:
This is a suit under 28 U.S.C. § 1498 (1976) seeking damages for the alleged infringement of plaintiffs patent No. 3,758,051 by the United States. After trial, Trial Judge Colaianni held that the patent is invalid under 35 U.S.C. § 102(b) (1976), which bars the issuance of a patent if "the invention was . . . described in a printed publication . . . or in public use ... in this country, more than one year prior to the date of the application for patent.”
Upon the plaintiffs exceptions to that decision, we reject the trial judge’s conclusion and remand the case to him to determine the other issues in the case.1
I.
Following the Soviet Union’s launching in 1957 of SPUTNIK, the world’s first artificial satellite, the Department of Defense and the National Aeronautics and Space Administration accelerated their efforts to create an effective synchronous satellite. A synchronous satellite is one whose orbital period is equal to the rotational period of the earth; the satellite would "hover” above a single, fixed point on earth. The satellite must be placed in a west-to-east orbit having a 22,750 nautical mile radius from the center of earth and a linear velocity of 10,090 feet per second.
[3]*3In order to conserve weight and energy, communications satellites are equipped with, directional antennas, and communication with earth is possible only when the satellite is oriented or positioned so that the directional beam can strike earth. Similarly, the solar cells used as a power source work most effectively when they are directed toward the sun. It is therefore essential that the communications satellite be equipped with a control system by which the proper orientation may be maintained.
The patent involved in this case — which Williams invented and assigned to the plaintiff — provides a sophisticated method for changing and therefore controlling the orientation of a satellite (also known as its attitude) in flight. In oversimplified terms, the invention consists of a process by which the orientation of the satellite can be changed in flight by the discharge from the satellite through openings on its surface of synchronized jet blasts of gas into the atmosphere. The proper timing and duration of those blasts are controlled through radio signals transmitted to the satellite from earth that activate and time the blasts. These instructions are sent following the receipt on earth of radio signals from the satellite that indicate the position and attitude of the body, on the basis of which calculations are made on earth which determine the instructions sent to the satellite. The control -signals sent from earth are synchronized with the spin cycle of the satellite, thereby activating the jet pulses in the proper phase of the spin cycle.
Williams filed his first application for a patent of the foregoing invention in April 1960. This application claimed the device described above, but did not describe the means to be used on earth to receive information from the satellite, make calculations, and transmit instructions to the satellite. After extensive proceedings before the Patent Office, in which the application was amended several times in attempts to satisfy the questions and doubts of the patent examiner, on April 21, 1964, Williams filed a continuation-in-part (CIP) application, on the basis of which the patent issued in September 1973.
A CIP application may contain subject matter from a prior application and additional matter not disclosed in the earlier application. Under 35 U.S.C. § 120 (1976), any new [4]*4matter in the CIP application has the filing date of that application; the earlier filing date of the prior application covers only material in the CIP application that also was disclosed in the prior application. The Williams CIP application for the first time described and disclosed in a drawing (Figure 12 of the application) the control device on earth that received radio signals from and transmitted them to the satellite.
In 1962, more than a year prior to the filing of the CIP application, Williams had described his invention in a paper given before the American Astronautical Society, and the invention had been publicly used in the SYNCOM satellite launched by the United States in 1963.
The patent that issued on the CIP application contains three claims, described below. If any of these claims in fact claims the Figure 12 control device as an element of the patented invention, the patent concededly is invalid under 35 U.S.C. § 102(b), because of the public disclosure of the invention more than a year before the CIP application was filed. The trial judge held that the patent does claim the control device and therefore is invalid. We reach a contrary conclusion.
II.
A. The governing principles are well-settled; the dispute is over their application to the facts here. Under 35 U.S.C. § 112 (1976), a patent application must include a specification containing
a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art ... to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
The section further provides that the specification "shall conclude with one or more claims, particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.” "[T]he claims made in the patent are the sole measure of the grant.” Aro [5]*5Manufacturing Co. v. Convertible Top Replacement Co., 365 U.S. 336, 339 (1961). See also Interdent Corp. v. United States, 209 Ct. Cl. 301, 306, 531 F.2d 547, 550 (1976).
The claims define the inventive concept that the patent embodies. The specifications, on the other hand, are designed to reveal how the invention may be put into practice, thereby defining the inventor’s monopoly and enabling others to practice the invention after the patent has expired. Although "it is fundamental that claims are to be construed in the light of the specifications and both are to be read with a view to ascertaining the invention,” United States v. Adams, 383 U.S. 39, 49 (1966), courts do "not read limitations into claims merely because they are disclosed in the specifications,” In re Walter, 618 F.2d 758, 768 (C.C.P.A. 1980). See also In re Prater, 415 F.2d 1393, 1404 (C.C.P.A. 1969) (specifications properly used to "interpret limitations explicitly recited in the claim”).
B. The Williams patent contains three claims.
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FRIEDMAN, Chief Judge,
delivered the opinion of the court:
This is a suit under 28 U.S.C. § 1498 (1976) seeking damages for the alleged infringement of plaintiffs patent No. 3,758,051 by the United States. After trial, Trial Judge Colaianni held that the patent is invalid under 35 U.S.C. § 102(b) (1976), which bars the issuance of a patent if "the invention was . . . described in a printed publication . . . or in public use ... in this country, more than one year prior to the date of the application for patent.”
Upon the plaintiffs exceptions to that decision, we reject the trial judge’s conclusion and remand the case to him to determine the other issues in the case.1
I.
Following the Soviet Union’s launching in 1957 of SPUTNIK, the world’s first artificial satellite, the Department of Defense and the National Aeronautics and Space Administration accelerated their efforts to create an effective synchronous satellite. A synchronous satellite is one whose orbital period is equal to the rotational period of the earth; the satellite would "hover” above a single, fixed point on earth. The satellite must be placed in a west-to-east orbit having a 22,750 nautical mile radius from the center of earth and a linear velocity of 10,090 feet per second.
[3]*3In order to conserve weight and energy, communications satellites are equipped with, directional antennas, and communication with earth is possible only when the satellite is oriented or positioned so that the directional beam can strike earth. Similarly, the solar cells used as a power source work most effectively when they are directed toward the sun. It is therefore essential that the communications satellite be equipped with a control system by which the proper orientation may be maintained.
The patent involved in this case — which Williams invented and assigned to the plaintiff — provides a sophisticated method for changing and therefore controlling the orientation of a satellite (also known as its attitude) in flight. In oversimplified terms, the invention consists of a process by which the orientation of the satellite can be changed in flight by the discharge from the satellite through openings on its surface of synchronized jet blasts of gas into the atmosphere. The proper timing and duration of those blasts are controlled through radio signals transmitted to the satellite from earth that activate and time the blasts. These instructions are sent following the receipt on earth of radio signals from the satellite that indicate the position and attitude of the body, on the basis of which calculations are made on earth which determine the instructions sent to the satellite. The control -signals sent from earth are synchronized with the spin cycle of the satellite, thereby activating the jet pulses in the proper phase of the spin cycle.
Williams filed his first application for a patent of the foregoing invention in April 1960. This application claimed the device described above, but did not describe the means to be used on earth to receive information from the satellite, make calculations, and transmit instructions to the satellite. After extensive proceedings before the Patent Office, in which the application was amended several times in attempts to satisfy the questions and doubts of the patent examiner, on April 21, 1964, Williams filed a continuation-in-part (CIP) application, on the basis of which the patent issued in September 1973.
A CIP application may contain subject matter from a prior application and additional matter not disclosed in the earlier application. Under 35 U.S.C. § 120 (1976), any new [4]*4matter in the CIP application has the filing date of that application; the earlier filing date of the prior application covers only material in the CIP application that also was disclosed in the prior application. The Williams CIP application for the first time described and disclosed in a drawing (Figure 12 of the application) the control device on earth that received radio signals from and transmitted them to the satellite.
In 1962, more than a year prior to the filing of the CIP application, Williams had described his invention in a paper given before the American Astronautical Society, and the invention had been publicly used in the SYNCOM satellite launched by the United States in 1963.
The patent that issued on the CIP application contains three claims, described below. If any of these claims in fact claims the Figure 12 control device as an element of the patented invention, the patent concededly is invalid under 35 U.S.C. § 102(b), because of the public disclosure of the invention more than a year before the CIP application was filed. The trial judge held that the patent does claim the control device and therefore is invalid. We reach a contrary conclusion.
II.
A. The governing principles are well-settled; the dispute is over their application to the facts here. Under 35 U.S.C. § 112 (1976), a patent application must include a specification containing
a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art ... to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
The section further provides that the specification "shall conclude with one or more claims, particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.” "[T]he claims made in the patent are the sole measure of the grant.” Aro [5]*5Manufacturing Co. v. Convertible Top Replacement Co., 365 U.S. 336, 339 (1961). See also Interdent Corp. v. United States, 209 Ct. Cl. 301, 306, 531 F.2d 547, 550 (1976).
The claims define the inventive concept that the patent embodies. The specifications, on the other hand, are designed to reveal how the invention may be put into practice, thereby defining the inventor’s monopoly and enabling others to practice the invention after the patent has expired. Although "it is fundamental that claims are to be construed in the light of the specifications and both are to be read with a view to ascertaining the invention,” United States v. Adams, 383 U.S. 39, 49 (1966), courts do "not read limitations into claims merely because they are disclosed in the specifications,” In re Walter, 618 F.2d 758, 768 (C.C.P.A. 1980). See also In re Prater, 415 F.2d 1393, 1404 (C.C.P.A. 1969) (specifications properly used to "interpret limitations explicitly recited in the claim”).
B. The Williams patent contains three claims.
The pertinent portion of claim 1, the broadest of the allowed claims, is as follows:
1. Apparatus comprising:
*****
e. means disposed on said body for providing an indication to a location external to said body of the instantaneous spin angle position of said body about said axis and the orientation of said axis with reference to a fixed external coordinate system;
f. and means disposed on said body for receiving from said location control signals synchronized with said indication;
g. said valve being coupled to said last-named means and responsive to said control signals for applying fluid to said fluid expulsion means in synchronism therewith for precessing said body to orient said axis in a predetermined desired relationship with said fixed external coordinate system.
Insofar as they are material in this case, the only differences between these clauses in claims 1, 2, and 3 is [6]*6that the word "means” in clause e of claim 1 is changed to "wide angle means” in claim 2 (clause f) and to "wide angle optical means” in claim 3 (clause e).
These claims do not incorporate the ground control device depicted in Figure 12. The trial judge stated that
what is being claimed by elements (e) — (g) is [1] apparatus carried by the satellite for transmitting information about its spin angle position to an external location, i.e, earth; [2] externally located apparatus for producing control signals which are synchronized with the spin angle position of the satellite; and [3] apparatus on the satellite for responding to the received control signals for processing the satellite.
But only the first and third of these three apparatuses are stated in the language of those clauses.
The claims do not refer to any "externally located apparatus.” The only references in the claims to anything external to the satellite are to "means disposed on said body for providing an indication to a location external to said body” and to means on the body for receiving signals "from said location” (items e and f, emphasis added). Although some devices and processes are necessary at the external location to receive and process the information sent there by the clause e "means” and to return the instructions relied on by the clause f "means,” the claims themselves do not embody any specific devices or processes outside the satellite.
The claims of the patent cover solely the orbiting satellite and no other object, device, means, or apparatus. The patent claims only an "apparatus comprising ... a body adapted to spin about an axis” (claim 1, clause a), with certain specified features; every successive clause of the claims covers one such feature and specifically relates back either to the "body” itself or to some other means or device attached to that body.
The only references in the claims to anything outside the satellite do not mention any ground-based device, let alone the specific ground-based device depicted in Figure 12. The claims of clauses e and f each comprise a means for performing a specified function and a statement of the function. See 35 U.S.C. § 112 (1976). The means claimed in [7]*7both clauses are "disposed on said body,” the "body” being the satellite.
These clauses do not claim or otherwise refer to any "means disposed” at the external location. While the functions there stated include interaction with the undes-cribed ground station — "providing an indication to a location external” and "receiving from said location control signals” — the functions claimed are those of the described means disposed on the satellite and are described from the perspective of the satellite, not the external location. On the other hand, the claims are silent about the functions performed at the external location (as well as all of the means used to accomplish those functions) — receipt of information from the satellite, performance of certain calculations, and transmission of instructions back to the satellite.
C. The specifications do not establish that the ground control device illustrated in Figure 12 is an element of the Williams patent. The specifications do not define the particular ground control device shown in Figure 12 as essential to the operation of the apparatus described in the claims. Instead, the specifications merely state that "[a]s an example of one means of controlling the starting time and duration of pulses to the jet control valves 54 and 55, in such a way as to result in thrust during the correct portion of each spin revolution, cam-controlled contacts or switches may be used” (col. 9, lines 25-29) (emphasis added).
The patentee’s use of this language indicates that he did not then view the Figure 12 device as the exclusive method of accomplishing properly synchronized jet pulses. Rather than describing an element of the invention, which the claims show to be only a satellite-based, apparatus, the specifications give an illustrative example of the kind of ground-based device that could be used in connection with the operation of the apparatus described in the claims. The specifications permit the use of any other means in lieu of the cam device that would achieve the same result.2 Indeed, [8]*8the only part of the addition to the specifications made in the CIP application that appears crucial to the invention is the spherical trigonometric equation, the use of which is described in column 10, lines 20-50. This is almost certainly not patentable. See, e.g., In re Christensen, 478 F.2d 1392 (C.C.P.A. 1973) (mathematical equations do not create patentable property rights).3
The history of the patent application itself shows that Williams, the inventor of the satellite, did not view the ground control device as part of his invention. In view of the vigor with which he prosecuted that application, he would not have jeopardized the grant of the patent by disclosing his invention in public print in 1962 and permitting it to be publicly used in 1963 if he had believed that the invention included the ground control device, which he did not disclose until he filed the CIP application in 1964.
In sum, the Williams application sought a patent upon a satellite and a satellite only. Although the application referred to a ground control system, this was unavoidable since it was impossible to disclose how the externally operated satellite functions without disclosing the external means of control. The discussion and illustration of the ground control device in the CIP application was added only because the patent examiner requested that additional information. This material was included in order to clarify [9]*9how the satellite could be used; it was not included for the purpose of describing in greater detail the invention itself. The invention was the satellite.
III.
The reason the trial judge concluded that the patent claims the Figure 12 ground controller is that because some external control device is essential to the operation of the Williams attitude control system, the patent for such a system necessarily must claim some external control device (and the Figure 12 device is the only one described in the patent). This view is at odds with the basic principle that it is not necessary to claim in a patent every device required to enable the invention to be used. As this court stated in Adams v. United States, 165 Ct. Cl. 576, 581, 330 F.2d 622, 626 (1964), aff’d, 383 U.S. 39 (1966):
It is evident that this section [35 U.S.C. § 112] does not require an inventor to disclose every possible way in which his invention may be used, nor does it limit the claims of the patent to the particular mode which the inventor considers best at the time of filing his application for patent.
See also Smith v. Snow, 294 U.S. 1, 11 (1935); Deering v. Winona Harvester Works, 155 U.S. 286, 302 (1894); In re Anderson, 471 F.2d 1237 (C.C.P.A. 1973).
In Deering, the Supreme Court stated that although "additional elements are necessary to render the device operative, it does not necessarily follow that the omission of these elements invalidates the claim, or that the precise elements described in the patent as rendering it operative must be read into the claim.” 155 U.S. at 302. As an illustration the Court pointed out that "[t]he invention of a needle with the eye near the point is the basis of all the sewing machines used; but the methods of operating such a needle are many,” and that the inventor of the sewing machine needle was not required to claim in his patent every machine in which the needle could be used or to restrict his patent to the method of use described in the application. Id.
[10]*10The same is true of the Williams attitude control system. It, like the needle, requires additional devices to make it operational, and there are many such devices (see note 2, supra). The specific ground control device described in the Williams patent is not an essential aspect of the invention, and the patent, like the patent for the sewing machine needle, is not limited to that one specific example. Just as the innovative aspect of the sewing machine needle was that the needle could be powered by a machine, so the innovative aspect of the Williams invention is that the attitude control system may be controlled from the ground. In neither case did the inventor of the patentable device (the needle and the attitude control system Controlled from the ground) also invent the device in conjunction with which the patented item was used (the sewing machine and the ground controller).
The principle reflects the practical reality that most inventions are designed to be used with other devices, both patented and unpatented. That fact, however, does not mean that the patented device necessarily also includes the other device in conjunction with which it is to be operated. Well-known examples are radio-operated garage door openers, in which a radio transmitter in the automobile or outside the garage activates the opening and closing mechanism of the garage door, and television set receivers, which cannot function without the signals transmitted from the broadcasting stations. The defendant concedes that "radio receivers and garage door openers can be and are claimed by themselves without also reciting the remotely located signal transmitter equipment.” It urges, however, that these devices differ from the Williams invention because both the garage door mechanism and the television set only receive signals, while the ground control device and the satellite both receive and transmit them.
This distinction is unconvincing. The need to use a separate device to enable a patented device to function is the same whether the separate apparatus merely receives or both receives and transmits radio signals. The critical fact is that the Williams invention, no less than the automatic garage door opener and the television set, can function only in conjunction with a signal from another [11]*11device. In all three instances that other device is not a part of the patented invention, but merely a separate apparatus which is required to be used when the invention operates.
The fact that the patentee amended his application to show and describe the ground control device does not establish that that device was an essential element of the invention that the claims covered. The problem with the original application with respect to the ground control device was not the failure to claim, such a device (since it was not a part of the invention), but to give sufficient information regarding the ground control device to enable one skilled in the art to practice the invention.
It was this deficiency in the information about the ground control device contained in the original application that the amplification of the specifications in the CIP application was designed to correct. That was a proper use of a CIP application. Such an application may, for example, contribute a "mere embellishment, or technical improvement, of a feature disclosed in the original application, which does not contribute to its novelty, utility, or non-obviousness,” Acme Highway Products Corp. v. D. S. Brown Co., 431 F.2d 1074, 1080 (6th Cir. 1970), cert. denied, 401 U.S. 956 (1971), or may merely elaborate on the disclosures of earlier applications, see Azoplate Corp. v. Silverlith, Inc., 367 F. Supp. 711, 732 (D. Del. 1973), aff’d, 506 F.2d 1050 (3d Cir. 1974), cert. denied, 421 U.S. 914 (1975).
IV.
In addition to the defendant’s contention that the patent was invalid under 35 U.S.C. § 102(b), the parties have raised various other issues. They include the validity of the patent under the nonobviousness standard of 35 U.S.C. § 103, the plaintiffs alleged "misrepresentation and other inequitable conduct,” and the defendant’s alleged infringement of the patent. Although the trial judge did not decide any of these other issues, the parties urge us to do so, and they have extensively briefed the questions before us.
We decline to decide those other issues. We think that the ultimate resolution of these complex and technical ques[12]*12tions would be aided if the trial judge initially examined and evaluated them.
CONCLUSION
The Williams patent is not invalid under 35 U.S.C. § 102(b). The case is remanded to Trial Judge Colaianni to file a recommended decision and findings on the other issues presented.