Washington — In the days of sail and cannon broadsides, communication in the US Navy meant sailors with signal flags. Today, it involves satellites, mile-long airborne antennas, and radio waves transmitted through rock. US submarines may soon receive messages via blue lasers shone on the sea.
The Walker spy case has focused new attention on United States military communications, command, and control, known as C3.
Navy officials say they will speed purchase of new equipment, because of secrets that may have been compromised. The Army and Air Force are trying to establish whether their communications are still secure.
But even before the Walker disclosures, communications was perhaps the fastest growing part of the US military budget. Spending on communications has jumped from $7.7 billion in 1980 to $18.8 billion for 1985. This will go for everything from jam-resistant satellites for controlling nuclear forces to fancy radios that will enable the services to better share information on the battlefield.
Military commanders have long recognized that reliable communications links are in many ways as important as firepower. The history of warfare is replete with blunders caused because messages were garbled or lost.
In August 1914, Kaiser Wilhelm at the last moment tried to stop the first move of German troops into Belgium. His telephone message did not get through -- and World War I began.
Much of the current emphasis on improving Pentagon communications involves control of nuclear-armed missiles, bombers, and submarines. In recent years a number of analysts have concluded that such strategic communications is the Achilles' heel of the US military, liable to disruption by a relative handful of Soviet warheads.
Early-warning radars, for instance, might be vulnerable to sabatoge or submarine attack.
Gophers apparently like to chew on the lead in cables connecting missile silos to launch centers.
``The state of US [communications] casts fundamental doubt on the ability of the United States to respond at all to Soviet nuclear attack,'' concludes Bruce Blair, a former Minuteman launch officer, in his new book, ``Strategic Command and Control.''
Early on, the Reagan administration made strategic communications one of its top defense priorities.
Among the improvements now being funded:
MILSTAR, a jam-resistant satellite system to link US officials with nuclear forces. Currently in the design stage, MILSTAR is the first communications system to be named a ``Brickbat'' top-priority program.
GWEN, a series of ground-based antennas that will use radio frequencies just off the AM dial to relay messages to bombers and missiles. A 10-antenna test system is scheduled for completion in 1985.
Blue-light lasers, beamed from space, to communicate with subs at sea. This futuristic technology is proceeding faster than expected, says a Pentagon spokesman, and will be tested under realistic conditions this year.
Talking to subs is particularly difficult, because seawater blocks most radio waves.
Currently, the Navy plans to communicate with subs in a crisis via 5,000-foot antennas towed behind planes, and charged with very low frequencey signals. These antennas, however, tend to fall off, says Daniel Ford, author of another recent book on strategic communications.
Thus the Navy is also building two ground-based extremely low-frequency (ELF) radio stations, which transmit signals to subs through the earth. One, near Clam Lake, Wis., is operational.
Mr. Blair concludes that Reagan administration efforts are at least a step in the right direction, but that they probably have not solved the whole problem of strategic communications vulnerability.
There is also a problem with ``the staggering cost of doing business'' in this area, said Assistant Defense Secretary Donald Latham in a speech earlier this year.
For instance, he estimates that terminals in B-1 bombers for receiving MILSTAR signals will cost several million dollars apiece.
Though attention and budget increases have been lavished on strategic systems, most military communications spending still goes for more-mundane, largely tactical equipment: field radios, telephone switching stations, etc.
The Army, for instance, wants to spend $12 million next year on PRC-70 radio sets and $5 million on teletypewriter terminals.
Shielding tactical communications from prying ears is today a large budget item -- and was so even before the Walker case called into question the security of certain systems.
Adm. James D. Watkins, chief of naval operations, has said the Walker revelations mean that the purchase of some new equipment will have to be acclerated, at a cost of millions. The Navy's detailed 1986 budget, which was prepared before the spy case broke, already proposes spending some $163 million on coding equipment.
One of the most persistent problems with tactical communications is getting the Army, Navy, and Air Force to build networks that will work together. The services at times seem to regard one another as major threats to Western civilization, with the result that the Marines develop an artillery control system that can't talk to its Army counterpart.
``Things are getting better, but there's still a long way to go,'' says a retired high-ranking military communications specialist.
Take JTIDS, the Joint Tactical Information Distribution System. In essence a fancy radio designed to give all services access to crucial battlefield data (such as location of enemy tanks), JTIDS has been 11 years in the making as the Navy and Air Force have fought over its design.
Congress, fed up, may just slash the $270 million requested for JTIDS in 1986.
On any future battlefield, complex tactical communications systems might make a large difference.
Along with JTIDS, the US military has been working on a host of systems that make cellular car phones look like tin cans with string.
Target radars have already progressed to the point where the Marines in Lebanon in 1983 tracked incoming artillery shells, matched up satellite data, and located enemy gun positions to within about 13 meters, according to the Armed Forces Journal.
But there is such a thing as too much data and communication, some analysts say.
If everyone is on the phone to everyone else, confusion may result, and soldiers in the field may not be able to react flexibly to changing situations. ``It's the plethora of gadgets that gets us in trouble,'' says William Lind, a defense analyst for Sen. Gary Hart (D) of Colorado.