Purpose of the Mercury-Redstone series is to qualify a production-line spacecraft with its many interrelated systems in a space environment.
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Background: Purpose of the Mercury-Redstone series is to qualify a production-line spacecraft with its many interrelated systems in a space environment. Later Redstone flights will be used to train the astronauts for orbital missions by subjecting them to rocket-boosted flight and periods of weightlessness.
In this MR-1 (Mercury Redstone One) test, the Mercury spacecraft will not be manned, nor will it contain any animals or biological specimens.
The blue-gray craft, which weighs about one ton, will follow a ballistic arc peaking at approximately 130 statute miles and splashing about 220 statute miles downrange in roughly 16 minutes. At burn-out, the cone-shaped spacecraft will be moving at a speed of a little over 4,000 statute miles an hour.
The flight will provide six G acceleration during the boost phase, about five and a half minutes of zero G (weightlessness) after booster and spacecraft are separated and as much as an eleven G deceleration during re-entry.
In rapid sequence at 35 miles altitude about 140 seconds after lift-off, (1) the booster will burn out; (2) the escape tower atop the spacecraft will be jettisoned and (3) three posigrade rockets at the base of the spacecraft will be fired to push the craft ahead and away from the booster.
Immediately following separation, an automatic stabilization and control system (ASCS) is used to remove any irregular spacecraft motions which might result from the separation action. The control system will steady the capsule's attitude by releasing pulses of hydrogen peroxide gas through jets at the neck and base of the craft.
About five seconds after separation, ASCS will swing the spacecraft around to the normal heat-shield-forward position.
As the craft nears the peak of its arcing flight, reaction control jets will shove the blunt face up 35 degrees above the retrorockets attached to the heat shield will be fired in rapid succession. Firing in the direction of flight, the retros in orbital flights would act as brakes, slowing the spacecraft slightly and thus letting gravity assert itself by pulling the craft back toward Earth.
It should be emphasized that while the retros are not needed to perform Mercury Redstone missions, they will be exercised as a part of the overall systems qualification program.
After the retro package is fired, it will be jettisoned from the base of the heat shield and ASCS will orient the craft in a heat-shield-down position for the plunge back to Earth. As the craft encounters atmospheric friction at roughly 50 to 45 miles altitude, ASCS will work to correct any spacecraft oscillations or pendulum motions which might begin during re-entry. The control system also will start the craft turning on its vertical axis in a slow top-like motion to reduce landing point dispersions.
At 42,000 feet, a pressure-sensitive switch will deploy a six-foot-wide drogue parachute which is to help curb the speed of the spacecraft which by this point should be moving at something like 600 miles an hour. Then at 10,00 feet, the antenna canister atop the capsule will be mortared off, unfurling a 63-foot-wide main chute. Simultaneously, radar chaff will be scattered to aid radar tracking and an explosive device called a SOFAR bomb, set to explode 2,500 feet underwater, will be released.
Upon touchdown, a switch jettisons the chute to avoid dragging the spacecraft in the wind. At the same time, various recovery aids go to work. These include sea-marking dye materials, radio beacons, and a high-intensity flashing light.
The conic spacecraft measures six feet across its blunt base and stands nine feet high. With escape tower in place on top the craft, the overall length from the base of the heat shield to the tip of the tower's aerodynamic spike is 24 1/2 feet.
Mounted on top of metal escape tower is a solid-propellant escape rocket with three nozzles pointed down and away from the spacecraft. In an off-the-pad abort situation, this rocket can pull the spacecraft off the booster and put 250 feet between the two in one second. The peak of such an escape maneuver is about 2,600 feet, followed by the normal landing sequence by parachute. Should trouble develop in the booster during the boost phase, the escape maneuver is essentially the same, however, the separation distance within one second is 125 feet instead of 250 feet.
In this, as in all Mercury Redstone and Mercury Atlas flights, the booster is equipped with an abort sensing mechanism. In this first Mercury Redstone test flight, however, the abort-sensing system will ride "open loop." That is, it will be wired to sense trouble in the booster but it will not be able to automatically trigger in the escape rocket as in later flights.The reason for having it on an "open loop." basis is to let engineers monitor its operation very closely in this first test of the Redstone system; in later flights it will be set to trigger the escape rocket automatically, should an impending launch vehicle failure be indicated.
In this test, an escape or abort command can be initiate by the launch director in the blockhouse, the Range Safety Officer in AMR Central Control or by the flight director in Mercury Control Center.
Within the double-walled nickel-alloy spacecraft shell is a pressurized cabin, flight instrument panel, several cameras, recovery aids, communications equipment and devices to monitor capsule and system stress and performance.
The communication system for MR-1 includes two telemetry transmitters which are completely redundant, each providing four channels to send information back to ground stations. Six of these channels will transmit continuous spacecraft attitude information -- pitch, roll and yaw, the three axial motions possible in such a craft. The other two channels will send data measurements from 90 different points throughout the spacecraft monitoring structural heating,cabin temperatures, pressures noise and vibration. In addition, on board recorders will record all this information for post-flight analysis. The spacecraft also is equipped with two separate command receivers either of which is capable of (1) signalling an abort or (2) firing the retrorockets.
Additional communications include two radar tracking beacons which will be used as the primary tracking means for position-fixing during parachute descent and can run for approximately 12 hours after landing.
Powering these and other electronic systems will be silver-zinc batteries.
The blunt end of spacecraft in this flight will be protected from re-entry heat by a beryllium shield. This differs from the ablative plastic shield to be used in later Atlas-boosted flights. In the Atlas flights, the shield will be subjected to temperatures of around 3,000 degrees F. In the Redstone flights, however, heat shield temperatures will hit only 20 degrees F. because of the greatly reduced spacecraft speed: 17,400 mph for Atlas flights against 4,000 mph for the Redstone.
In the Redstone flights, temperatures on the spacecraft's corrugated metal "shingles" forming the conic afterbody will run considerably higher -- 600 degrees F. is estimated -- than those on the beryllium shield surface (200 degrees F.).
Looking out one spacecraft port will be a 70mm camera designed to record what a man would see from that vantage point. Also a 16mm camera, installed to the left of where the pilot's display panel will record the functions of the cockpit instrument display panel. There will be no astronaut couch in this capsule. In its place will ride instrument boxes and ballast weights.
Overall control for the MR-1 test will be exercised by the Mercury Operations Director in the Mercury Control Center. Detailed flight control will be the responsibility of the Flight Director and a staff of flight controllers operating from consoles in Mercury Control Center.