Project FIRE
Project FIRE (also Flight Investigation of the Reentry Environment , German: Flight investigation of the re-entry environment ) was a NASA research program that tested technologies for the heat shield of the Apollo capsules . The aim was to obtain readings from various heat shield materials at previously unattainable speeds upon reentry .
The two missions of the FIRE program were carried out by the Langley Research Center . The Republic Aviation Company developed and built the FIRE re-entry bodies, Radio Corporation of America (RCA) supplied the communication systems and Ling-Temco-Vought built the acceleration unit ("Velocity Package") . A Convair Atlas-D served as the launch vehicle .
The results of these missions enabled the Apollo capsules to safely enter the earth's atmosphere after their flight to the moon.
Structure of the FIRE re-entry vehicle
The 86.5 kg re-entry body had the cone-shaped appearance of a scaled-down Apollo command module. The blunt side, with which the object first re-entered the earth's atmosphere, carried an ablative heat shield consisting of four segments . Inside the re-entry body were temperature measuring devices to record the efficiency of the materials, as well as radiometers to measure the thermal radiation in the vicinity of the re-entry body. The data was initially saved on tape, as a radio link was initially impossible due to the ionization of the surrounding air during re-entry . After the FIRE capsules were slowed down so that the ionization stopped, the collected data were sent several times until the impact. A recovery device was not on board, so that the re-entry bodies were lost when they hit the sea surface.
Launcher
An Atlas D rocket with an Antares 2 upper stage was used to start each mission. Although the Atlas-D first stage largely corresponded to the ICBM version, these were stages that were built explicitly for these NASA missions.
The Antares-2 upper level came from the Scout program, where it was used as the third level. This stage was connected to the Atlas rocket via an adapter section, which, after being separated from the launch vehicle, ensured the correct alignment of the Antares stage and stabilized it with the help of two small rocket motors . The adapter section was disconnected shortly before the ignition. The Antares engine burned for 30 seconds and accelerated the FIRE capsule to a speed of over 40,000 km / h. After the Antares stage had burned out, the FIRE capsule was removed. Since it was already mounted on the upper level with the heat shield first, it was no longer necessary to align it afterwards. The separated Antares stage was caused to tumble by a small rocket attached to the payload adapter so that it was exposed to greater air resistance on re-entry and thus moved further away from the FIRE re-entry body.
Structure of the Antares upper level
Payload adapter with wobble rocket motor
Models of the payload mounts and the FIRE capsule
Mission history
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The Atlas-D as the first stage carried the FIRE payload including the upper stage ("Velocity Package") on a ballistic suborbital trajectory . After the first stage had burned out, the upper stage together with the position control unit in the adapter section was separated. These initially flew without propulsion on the ballistic trajectory, which reached a peak height of 805 km. The upper stage was brought into the correct orientation by the position control unit and then set in rotation for stabilization. On the descending branch of the trajectory, the upper stage ignited after about 26 minutes of flight time and accelerated the payload to over 40,000 km / h. The FIRE payload was then separated from the upper stage and released into the atmosphere.
During re-entry, the temperature of the heat shield was continuously measured and the environmental conditions of the ionized atmosphere outside the capsule were recorded and stored on the data recorder. As soon as radio contact was possible again after this phase, the data was sent to a ground station on Ascension Island as well as aircraft and track tracking vessels in the target area (including the USNS General HH Arnold (T-AGM-9) on the first mission and the USNS Twin Falls (T-AGM-11) on the second). The capsules hit the Atlantic unchecked and were not recovered.
FIRE 1 reached a speed of 40,501 km / h on re-entry into the earth's atmosphere, which led to a maximum temperature of 11,400 K of the heat shield. The probe successfully transmitted the collected measurement data to the ground stations during the re-entry phase. After a flight time of 32 minutes, the probe hit the South Atlantic.
FIRE 2 , also "flying Thermometer" ( "flying thermometer") called, reached a maximum altitude of 805 km. The upper stage ignited 26 minutes after take-off and accelerated the re-entry vehicle to a speed of 40,877 km / h, with temperatures of up to 11,206 K being measured on the heat shield. The data was successfully transmitted to the ground stations during re-entry. The mission lasted 32 minutes and ended with the probe impacting the Atlantic at a distance of 8,256 km southeast of the launch site.
Flights
| Surname | date | Launch rocket | Starting place | Dimensions | Remarks |
|---|---|---|---|---|---|
| FIRE 1 | April 14, 1964 | Atlas-D Antares-2 | Cape Canaveral Air Force Station | 86.5 kg | success |
| FIRE 2 | May 25, 1965 | Atlas-D Antares-2 | Cape Canaveral Air Force Station | 86.5 kg | success |
Web links
- FIRE at skyrocket.de (English)
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- ↑ a b c d e NASA: Project FIRE Integrated Post Flight Evaluation Report - Flight No. 1 (PDF; 8.4 MB)
- ↑ a b c d e NASA: Project FIRE Integrated Post Flight Evaluation Report - Flight No. 2 (PDF; 16.8 MB)
- ^ NASA The Apollo Spacecraft - A Chronology. Volume II, Part 2 (c)
- ^ NASA The Apollo Spacecraft - A Chronology. Volume III, Part 1 (h)