RESULTS OF THE THIRD U.S. MANNED ORBITAL SPACE FLIGHT, OCTOBER 3, 1962

 

3. AEROMEDICAL ANALYSIS

By Charles A. Berry, M.D., Chief, Aerospace Medical Operations Office; Howard A. Minners, M.D., Aerospace Medical Operatiors Office; Ernest P. McCutcheon, M.D., Aerospace Medical Operations Office; and Richard A. Pollard, M.D. Aerospace Medical Operations Office

 

Summary

 

[23] Astronaut Walter M. Schirra, Jr., incurred no detectable physiologic decrement during his space flight which included over 9 hours of weightlessness. His body functions since the flight have remained normal and unchanged from their healthy preflight condition. A variation of the astronaut's instantaneously observed heart rate response was noted during flight. Immediately following recovery, an orthostatic rise in heart rate accompanied, panted by a fall in systolic blood pressure was observed for a brief period. Inflight ionizing-radiation monitoring showed that the astronaut sustained no significant exposure.

 

Introduction

 

The aeromedical findings obtained during the MA-8 mission amplified those resulting from previous manned space flights (refs. 1 to 9). The astronaut's state of health and his medical fitness for space flight were continuously evaluated during his preflight preparation. These accumulated data served to familiarize the aeromedical flight controllers with the astronaut's normal physiological responses and also provided a baseline with which to compare inflight and postflight findings. These preflight, inflight, and postflight medical findings are presented chronologically in this paper. The preflight and flight chronologies are subdivided into two classifications, clinical examinations and physiological observations. The postflight findings are grouped into an aeromedical history and physical examinations. Finally, a series of special studies for the MA-8 mission are presented.

The spacecraft environment materially affects the pilot's physiological responses; thus, the discussion of the environmental control system performance in the Life Support System section of paper 1 complements the physiological observations presented herein.

 

Preflight

Clinical Examinations

 

The clinical examinations of the astronaut consisted of aeromedical histories, physical examinations, clinical laboratory tests, X-rays, an electrocardiogram (ECG), an electroencephalogram (EEG), and an audiogram..

Aeromedical history.- Astronaut Schirra spent most of the time from June 1962 to the launch date of October 3, 1962, at Cape Canaveral, Fla., in preparation for the MA-8 mission. During this period, he chose swimming and water skiing for preflight physical conditioning. In the several days immediately prior to flight, he did not undertake direct physical conditioning. A controlled diet which provided a balanced menu was begun on September 21, 1962. A low-residue diet was followed, as planned, for the 3 days before flight. The menu for meals included in the low-residue diet is presented in table 3-I. Astronaut Schirra reported minimal difficulty in becoming accustomed to this diet. All of the 325-cc fluid intake on the morning of launch from awakening to lift-off, occurred at breakfast and consisted mostly of orange juice. Astronaut Schirra reported that shortly before lift-off, he was aware of an emptiness in his stomach and the possibility occurred to him that he might become nauseated during the flight. This...

 

[24] Table 3-I. Low Residue Diet.

September 30, 1962

October 1, 1962

October 2, 1962

October 3, 1962

Breakfast

09:00 a.m.
Grapefruit juice
Cream of rice
Scrambled eggs
Canadian bacon
Toast, butter
Jelly
Coffee
06:15 a.m.
Orange juice
Baked egg, bacon
Toast, butter
Jelly
Coffee
06:30 a.m.
Orange-grapefruit juice
Cream of rice
Soft cooked egg
Canadia bacon
Toast, butter
Jelly
Coffee
02:10 a.m.
Orange juice
Scrambled eggs
Fish
Steak
Toast, butter
Jelly
Coffee

Lunch

-

12:00 noon
Tomato juice
Noodles with veal
Cottage cheese
Melba toast
Butter
Pound cake and apricots
Tean and coffee
11:30 a.m.
Chicken noodle soup
Meat loaf on toast
Peas
Sherbet
Coffee and tea

-

Dinner

04:00 p.m.
Shrimp cocktail
Crackers
Baked chicken
Rice, peas
Hard rolls, butter
Sherbet, cookies
Coffee and tea
05:00 p.m.
Consomme, crackers
Steak
Potato, green peas
Hard rolls, butter
Jello
Coffee and tea
05:30 p.m.
Pineapple juice
Roast beef
Baked potato
Wax beans
Hard roll, butter
Angel food cake and peaches
Coffee and tea

-

 

....sensation is attributed simply to the fact that he had not eaten for 5 hours. During the 155-minute period after his insertion into the spacecraft and prior to launch, he voided three times into the urine collection device.

The MA-8 aeromedical countdown differed from those of previous orbital flights only in the times alloted for each activity and the time when the pilot was awakened on launch day. A comparison with the countdowns of previous orbital missions is provided in table 3-II. Such changes reflect not only operational requirements to complete certain tasks, but also represent an effort to provide the pilot with a maximum amount of sleep prior to the mission. He obtained 5 hours of sound sleep immediately before the mission. No medication was given.

Physical examinations.-Abbreviated physical examinations were conducted by the MA-8 Crew Flight Surgeon prior to each of the preflight activities listed in table 3-III. A somewhat more extensive examination was conducted 15 days prior to flight. Also, a comprehensive medical evaluation was accomplished...

 

Table 3-II.-Aeromedical Countdown Summary

[AII times are e.s.t]

MA-6

MA-7

MA-8

Pilot awakened

2:20 a.m.

1:15 a.m.

1:40 a.m.

Nominal launch

8:00 a.m.

7:00 a.m.

7:00 a.m.

Time to nominal launch, hr:min

5:40

5:45

5:20

Actual launch

9:47 a.m.

7:45 a.m.

7:15 a.m.

Time to actual launch, hr:min

7:27

6:30

5:35




[25] Table 3-III.- Abbreviated Preflight Activities

Date

Activity

September 1962:

10

Simulated flight, suited and with sensors

13

Simulated flight, suited and with sensors

15

Procedures trainer, MCC suited

18

Medical evaluation

20

Procedures trainer, MCC suited

21

Began controlled diet

28

Launch simulation, suited and with sensors

29

Simulated flight, unsuited

30

Began low-residue diet

October 1962:

1

Comprehensive medical evaluation

3

Aeromedical countdown, flight, postrecovery examination

4 and 5

Aeromedical and engineering debriefing

6

Departure from debriefing site

9

Return to Cape Canaveral

 

...by a team of specialists 2 days before the flight. This evaluation included an audiogram, a chest X-ray, and an electrocardiogram.

An electroencephalogram accomplished on May 17, 1962, was deemed adequate for purposes of comparison with the postflight electroencephalogram and was not repeated before the flight. All of these medical evaluations (tables 3-lV to [3-V)] 3-VI) revealed a healthy and alert pilot, fit for his flight assignment.

 

Physiological Observations

 

The physiological observations are based on data from the sensors on the pilot and sensors of the spacecraft environment. Physiological data for Astronaut Schirra covering a total observation time of 23 hours and 27 minutes were obtained from the following sources:

1. Dynamic tests (treadmill, tilt table, and cold pressor) conducted at the Lovelace Clinic, Albuquerque, New Mexico, in March 1959.

2. The Mercury-Atlas three-orbital pass simulation conducted at the U.S. Naval Aviation Medical Acceleration Laboratory (AMAL) in Johnsville, Pennsylvania, on September 22, 1961.

3. A simulated flight on May 4, 1962, conducted at the launch complex at Cape Canaveral as a part of the MA-7 prelaunch preparation.

 

Table 3-IV.-Clinical Evaluation.

[All times are e.s.t., October 3, 1962]

Preflight at Cape Canaveral 2:46 a.m. (a)

Postflight onboard the aircraft carrier 6:05 p.m. (b)

Temperature (oral), °F

97.6

99.4

Pulse rate, beats/min

64 (supine)

92 (supine)

Blood pressure, left arm, mm Hg

120/78 (supine)
122/85 (standing)
118/78 (standing)

Respiratory rate, breaths/min

14

-

Weight (nude, bladder empty), lb

176 3/4

172 1/4

Comments

Hematome, right inguinal region; otherwise no abnormalities, including ECG, audiogram, and chest X-rays performed October 1, 1962.

Abrasions of right knuckles; pressure points over both acromial processes; and oethrostasis. Otherwise normal.

a Unchanged from the several other preflight examinations.
b Repeated examination on October 4, 1962, did not reveal orthrostasis abrasions and pressure points were resolving. Complete examination of October 1, 1962, was repeated on October 4 and 5, 1962; no significant change was detected.

 

 

[26] Table 3-V.-Peripheral Blood Values

Determination

Preflight

Postlanding

-15 1/2 hr

-1 1/2 hr

+ 5 hr

+ 14 1/2 hr

+ 51 hr

Hemoglobin (Cyanmethemoglobin method, grams/100 ml

15.0

-

14.5

15

14.7

Hematocrit, percent

44

47

45

46

43

Red blood cells, millions/mm3

5.0

-

4.7

4.8

4.6

White blood cells /mm3

9,800

-

10,350

8,400

9,400

Differential blood count:

Lymphocytes, percent

34

-

31

49

47

Neutrophiles, percent

62

-

63

46

51

Monocytes, percent

3

-

4

3

1

Eosinophiles, percent

1

-

2

2

1

Basophiles, percent

0

-

0

0

0

Platelets/mm3

adequate

-

adequate

274,000

294,000

Sodium, mEq/l

152

150

147

145

145

Potassium, mEq/l

3.9

4.1

3.9

3.8

4.3

Chloride, mEq/l

102

108

107

103

104

Calcium, mEq/l

5.2

5.9

5.6

5.2

5.1

Protein (total), g/100ml

8.0

8.0

7.0

8.1

7.0

 

4. Simulated flights conducted with the spacecraft in the altitude chamber at Cape Canaveral on April 17, 1962, and with the spacecraft at sea level on August 14, 1962.

5. Simulated flights on September 10 and 14, 1962, and a simulated launch on September 28, 1962, all of which were conducted at the launch complex.

6. Records obtained from the biosensor checkout in the hangar, in the transfer van, and from the blockhouse during the launch countdown on October 3, 1962.

Biosensor system.-The Mercury biosensor system for this mission consisted of two sets of electrocardiographic (ECG) leads, a rectal temperature thermistor, an impedance pneumograph, and the blood-pressure measuring system (BPSIS). Reports of the results for previous missions (for example, ref. 8) contain most of the details of the biosensor system. Changes to this system for the MA-8 mission were as follows: The ECG electrode on the right lateral chest midaxillary line was moved slightly lower to minimize muscle artifact. The ECG electrodes were affixed to the skin with a double-backed adhesive tape, such as that used for a colostomy, and this tape was fitted to the rubber ring of the sensor. The sensor paste was changed from the previously used bentonite-calcium chloride compound to a combination of carboxypolymethylene and Ringer's solution. Carboxypolymethylene is a hygroscopic, polymerized carrier for the ions needed to provide electrical continuity, is more soluble, and is easier to work with than the bentonite paste. The 10-times-isotonic Ringer's solution not only retained the necessary conductivity and low impedance required, but also afforded decreased skin irritation after prolonged contact.

Considerable study and detailed evaluation of the BPMS after the MA-7 mission demonstrated a definite need to change the criteria for adjusting the amplification of the sounds picked up by the microphone, which is located over the brachial artery-. These sounds should correspond to those heard with a clinical stethoscope during cuff pressure decay if an accurate interpretation of BPMS data is to be achieved. Repeated comparisons of clinical blood-pressure readings with those obtained using the BPMS allowed determination of an optimum controller gain setting specifically for the flight astronaut. To provide more freedom in the pressure suit,....

 

[27] Table 3- VI. Urine Summary.

Determination

Preflight

Inflight

Postlanding

- 1 day

+ 6 hr

+ 17 1/2 hr

+ 23 hr

+ 50 hr

+ 53 hr

+ 56 1/2 hr

+ 61 hr

+ 63 hr

+ 69 hr

Volume, cc

-

(a)

233

323

150

440

460

410

850

125

375

Specific gravity

1.010

1.010

1.018

1.021

1.021

1.013

1.010

1.014

1.020

-

-

Osmolarity, milliosmoles

593

595

848

995

951

442

266

609

262

301

568

pH

6.0

Acid

Acid

Acid

Acid

6.0

7.0

6.0

-

-

-

Albumin, glucose, ketones, bile

0

0

0

0

0

0

0

0

0

0

0

Sodium, mEq/l

103

86

107

47

54

69

62

112

35

19

66

Potassium, mEq/l

47

49

58

46

69

34

18

38

14

19

59

Chloride, mEq/l

127

106

103

47

93

62

32

70

24

24

91

Calcium, mEq/l

8.5

6.1

4.8

8.4

8.4

7.0

2.9

4.0

2.2

1.6

3.1

Microscopic examination (High power field)

Occasional white blood cells; few squamous cells

-

4 to 5 white blood cells; occasional red blood cells; mucuous threads rare granular cast, some epithelial threads

Occasional white blood cells; occasional epithelial cell, no red blood cells

Occasional white blood cells; amorphous sediment

3 to 9 white blood cells; minimal mucuous

Occasional white blood cells

Occasional white blood cells

-

-

-

a Most of the inflight specimen was lost into the Mercury pressure suit. A total of 292 was recovered.

 

[28]....the thickness of the BPMS cuff was decreased without change in bladder size. The diameter of the hose leading from the cuff to the suit connection was also decreased. The microphone, cuff, and controller were all fitted and calibrated specifically for Astronaut Schirra. These changes did not affect the cuff filling or bleed-down times, and the basis design of the BPMS system was unchanged.

During preflight testing at the launch complex, the BPMS automatic timer failed. This failure made it necessary for the astronaut to depress the manual stop button at cycle completion in order to return the telemetry signal from BPMS to ECG II. This method of manual operation was used throughout the flight.

The body-temperature instrumentation failed 6 minutes before launch, with the readout going to full scale. At approximately the middle of the second orbital pass, a nominal value reappeared, but thereafter the signal was somewhat intermittent.

The respiratory trace was obtained by measuring transthoracic impedance which is directly proportional to thoracic volume. The variation of thoracic impedance correlates well with spirometer data, although the correlation is not linear. The impedance pneumograph system consists of a 50-kc oscillator, a 50-kc amplifier, a detector, and a low-frequency amplifier. The output of the oscillator is applied across the chest by electrodes in each midaxillary line at the level of the subject's sixth rib. These electrodes, the conductive paste, and the methods of attachment are identical to the ECG electrode system previously described. The oscillator output is varied by means of a potentiometer so that the inspiratory peaks remain on scale on the direct writing recorder except during exceptionally deep breathing. Even when the range is exceeded, respiratory rate can still be determined unless it is accompanied by excessive body movement. Body movements of the pilot can make the respiratory trace difficult to interpret, but the inherent restrictions on such movement of the spacecraft design keep motion artifact to a minimum. The unit does not indicate instantaneous tidal volume, but it does provide a general trend of changes in chest volume. Inspiration is distinguishable even during the thoracic volume changes that occur with speaking.

Baseline data.- Baseline physiological data were obtained during the preflight activities listed in table 3-VII. This table also summarizes all available data on heart rate and respiration rate. The rates from the dynamic simulation at the Johnsville AMAL were determined by counting for 30 seconds during each minute. Other heart and respiratory rates were obtained by counting for 30 seconds every 3 minutes. Rates for the final 10 minutes of the MA-8 launch countdown were determined by counting for 30 seconds every minute. The mean prelaunch heart and respiration rates were similar to those obtained during other procedures, and all values were within physiologically acceptable limits. Preflight body temperatures ranged from 97.0°F to 97.9°F until the signal failed.

Examination of the ECG waveforms during prelaunch activities showed sinus arrhythmia, infrequent premature atrial contractions, and rare premature ventricular contractions. During the actual launch countdown, a single premature atrial contraction occurred.

Blood-pressure data are summarized in table 3-VIII. The values for the "Special BPMS Test" of July 25, 1962, were collected from a series of comparisons of BPSIS readings with those obtained using the standard clinical technique. These values were obtained early in the astronaut's preflight preparation period to determine at an early date the proper gain adjustment of the BPMS amplifier. Random clinical determinations were obtained from routine annual physical examinations and from examinations associated with various prelaunch activities. The preflight clinical values and BPMS readings are similar and represent normal physiological responses.

 

Flight Responses Clinical Evaluation

 

Data for the inflight clinical evaluation are obtained from the voice transmissions of the aeromedical monitors and postflight debriefing queries. It is, in the strictest sense, not the usual clinical evaluation, because the telemetered physiological responses serve as a substitute for a normal physical examination.

Despite the increase of 4 1/2 hours in the duration of weightlessness above that experienced in each of the two previous manned...

 

Click here to go to the accessible version of table 3.7 and table 3.8

[29] Table 3-VII.- Summary of Heart Rate and Respiration Data From Physiological Monitoring.

Date

Procedure

Duration of observation, hr:mn

Heart rate, beats/min

Respiration rate, breaths/min

Number of dterminations

Standard deviations 2 (sigma)

Range

Mean

Number of determinations

Standard deviations, 2 (sigma)

Range

Mean

Preflight

March 1959

Lovelace Clinic dynamic tests

Variable

39

(a)

68 to 160

96

None recorded

Septmenber 22,1961

Mercury-Atlas Centrifuge dynamic simulation

1:07.5

75

50 to 78

48 to 78

64

25

9 to 15

7 to 18

12

May 4, 1962

MA-7 launch-pad simulated flight

1:09

24

53 to 91

58 to 88

72

19

10 to 22

10 to 24

16

April 17 and August 14, 1962

Hangar simulated flights

9:47

87

52 to 78

51 to 76

65

19

14 to 26

14 to 24

20

September 10, 1962

Launch pad simulated flight 1A.

3:09

69

45 to 65

43 to 72

55

68

14 to 26

10 to 28

20

September 14, 1962

Launch pad simulated flight 2A.

2:35

68

54 to 82

52 to 86

68

68

14 to 30

12 to 28

22

September 28, 1962

Launch pad simulated launch.

3:07

72

49 to 73

46 to 74

61

71

12 to 28

9 to 26

20

October 3, 1962

Launch countdown

2:33

61

64 to 80

58 to 88

72

61

17 to 23

16 to 26

20

Inflight

October 3, 1962

Inflight

9:13

220

50 to 102

56 to 121

76

220

11 to 27

10 to 43

19

Postflight, clinical

October 3 and 4, 1962

Debriefing onboard recovery ship

Variable

22

52 to 112

56 to 104

82

None recorded

a These data are included for completeness, but the conditions were very different from the other procedures.

 

[29] Table 3-VIII.- Summary of Blood-Pressure Data

Date

Procedure

Mean blood pressure, mm Hg

Systole

Diastole

Mean pulse pressure, mm Hg

Number of dterminations

Standard deviations 2 (sigma)

Range, mm Hg

Mean, mm Hg

Number of determinations

Standard deviations, 2 (sigma)

Range, mm Hg

Mean, mm Hg

Preflight, clinical

March 1959

Lovelace Clinic dynamic tests

119/67

39

(a)

90 to 164

119

39

(a)

52 to 84

67

85

July 25,1962

Special BPMS test

104/75

27

92 to 116

94 to 116

104

27

62 to 88

64 to 94

75

29

1960 to October 3, 1962

Random clinical derterminations

115/76

13

103 to 127

100 to 122

115

13

62 to 90

64 to 84

76

39

Preflight, BPMS

September 22, 1961

Mercury-Atlas dynamic simulation on centrifuge

133/96

11

111 to 115

115 to 150

133

11

68 to 124

76 to 120

96

37

July 25, 1962

Special BPMS test

108/67

28

(a)

94 to 126

108

28

(a)

54 to 100

67

41

May to October, 1962

Hangar and launch complex tests

107/70

31

92 to 122

94 to 123

107

29

58 to 82

58 to 80

70

37

October 3, 1962

Prelaunch (hangar, transfer van, and blockhouse)

117/80

14

103 to 121

110 to 143

117

14

66 to 94

71 to 94

80

37

Inflight, BPMS

October 3, 1962

Inflight

126/69

20

116 to 136

111 to 158

126

16

64 to 74

59 to 75

69

57

Postflight, clinical

October 3 and 4, 1962

Debriefing onboard carrier

112/78

12

92 to 132

94 to 120

112

12

70 to 86

70 to 84

78

37

a These data are included for completeness but the conditions were very different from the other procedures.

 

[31]....orbital space flights, no untoward sensations were reported by Astronaut Schirra, and the assigned inflight tasks were performed without difficulty. Specifically, he was not nauseated and did not vomit. Although, the astronaut was never hungry during the flight, he ate the contents of two tubes containing food, one of peaches and the other of beef with vegetables, without difficulty. He experienced no urge to defecate during the mission, but he did report a moderate amount of inflight flatulence unaccompanied by eructation. Vision and hearing were normal. Astronaut Schirra moved his head as required by his scheduled tasks during the weightless period, including times when the spacecraft was in attitude-free drifting flight, but he experienced no vestibular disturbance or disorientation. The noise and vibration of powered flight were not considered abnormally stressful.

During the flight the pilot drank about 500 cc of water. He urinated three times before lift-off and three times during the flight, the last time just before retrofire. Bladder sensation and function were reported to be normal. Unfortunately, on landing, the urine collection device failed at its attachment to the body and all but 292 cc of the urine was lost.

A few minor problems were encountered. Astronaut Schirra was unable to reach some of the items in the special equipment storage kit....

 

Table 3-IX.- Results of Orientation Test.

Ground elapsed time, hr:min

Target

Result

Error

03:15

Manual fuel lever

Manual fuel lever

None

Yaw attitude indicator

Rivet above clock in 10:30 position

1 1/2 inches down and right

Emergency rate lever

Emergency rate lever

None

05:19

Manual fuel lever

Right of manual fuel lever

2 inches right

Yaw attitude indicator

270° mark on yaw attitude indicator

3/4 inches left of center of instrument

Emergency rate lever

Emergency rate lever

None

08:21

Manual fuel lever

Manual fuel lever

None

Yaw attitude indicator

20° mark on yaw attitude indicator

1/2 inch right of center of instrument

Emergency rate lever

Side of hand hit box of emergency rate lever. Index finger was on target

None

 

...located near his right shoulder. This inaccessibility resulted not only from the usual restrictions in motion imposed by the restraint harnesses and suit, but also because the equipment kit had been located nearer the right shoulder for this mission. Consequently, he was unable to evaluate certain items as planned. He also discovered that many items in the equipment kit were covered excessively with Velcro and were, therefore, difficult to remove from stowage. Velcro is a cloth having two different but mutually adhesive surfaces.

During the fourth or fifth orbital pass, a fluid was deposited onto the left inner surface of the helmet faceplate. This fluid obscured the pilot's vision to some degree and forced him to turn his head more than usual to look through the remaining area of the visor that was clear. A postflight analysis proved that this fluid was perspiration.

The astronaut stated he was warm and perspired moderately during the first orbital pass when he was subjected to an elevated suit-inlet temperature. However, he said he was not uncomfortably hot during this period. Medical evaluation of telemetered data during this period indicated that the astronaut was physiologically capable of continuing the flight. The astronaut believed he would be able to control the suit-inlet temperature during the next pass and did so, even to the extent of becoming [32] "a little cool" during the fifth and sixth passes. Otherwise, he was comfortable throughout the flight.

Weightlessness was described as "very pleasant," but there was no exhilaration, euphoria, breakoff phenomenon, or other unusual psychological reaction.

During this flight, in addition to utilizing programed times for self-evaluation of orientation to his environment, Astronaut Schirra performed a specific test of orientation. At three different times, he closed his eyes and attempted to touch each of three instruments with his index finger. Results were recorded on the onboard tape and are summarized in table 3-lX. The results show that, in nine attempts, the pilot made five "direct hits" and four "near misses," which included a maximum error of 2 inches. These errors are scattered, but suggest that the third test was the most accurate. Astronaut Schirra concluded that his performance improved with practice and that he performed equally as well during flight as he had done in the Mercury procedures trainer.

Astronaut Schirra developed slight nasal congestion during the final two orbital passes. This congestion caused no difficulty in clearing his ears and did not affect normal respiration. About 4 hours after recovery, he developed mild rhinorrhea which completely disappeared by the next day.

 

Physiological Observations

 

The total inflight bioinstrumentation monitoring time was 9 hours and 12 minutes. In addition to the continuous records of biosensor data recorded on board, information was obtained through reports from the aeromedical flight controllers around the Mercury network, voice reports by the pilot, and, after the flight, from the film exposed in the pilot-observer camera.

The inflight physiological responses are summarized in tables 3-VII and 3-VIII. Heart rates in beats per minute were obtained by counting 30 seconds of each minute from lift-off to 10 minutes ground elapsed time (g.e.t.), and from 08:48 to 09:13 g.e.t. Values for the remainder of the flight were obtained from 30 second counts every 3 minutes. Biosensor disconnect occurred at approximately 09:13 g.e.t. The mean inflight heart and respiratory rates are not significantly different from the mean preflight values. The maximum heart rate during the launch phase was 112 bouts per minute, with a minimum of 102 beats per minute. The maximum heart rate during the orbital phase was 121 beats per minute which occurred just after orbital insertion. Thereafter, it gradually declined, with the slowest rate being 56 beats per minute. During reentry, the maximum heart rate was 104 beats per minute. These responses are within expected physiological ranges.

Careful observation of the ECG reveals frequent variations of the R-wave to R-wave intervals, indicative of an increase and slowing of heart rate. These variations were apparently unrelated to physical activity, and their magnitude was greater than Astronaut Schirra's normal sinus arrhythmia. The reason for this phenomenon, most marked from the fourth to the last orbital pass, is unknown.

The maximum respiratory rate during powered flight of 37 breaths per minute was observed just prior to insertion into orbit when the pilot was experiencing maximum launch acceleration. During weightless flight, respiration rates were close to the mean value. During reentry at 09:05 g.e.t., the respiration rate reached a maximum of 43 breaths per minute and was coincident with maximum reentry acceleration. Thereafter, the rate declined to 20 breaths per minute at biosensor disconnect. These values are also within anticipated physiological ranges.

As shown in table 3-VIII, a total of 20 BPMS cycles were obtained at random intervals throughout the flight. The systolic levels were easily distinguishable for all 20 cycles. Since the automatic BPMS timer was not functioning, premature cutoff of the BPMS signal by the astronaut made four of the diastolic points questionable, and these values are absent from the tabular data. All of the values which were observed during the flight are considered to be normal for Astronaut Schirra. The mean pulse pressure of 57 mm Hg does not represent a physiologically significant elevation from the other values.

Examination of the ECG trace during flight. showed no change from the pilot's preflight waveforms. One premature atrial beat, one premature ventricular beat, and one fusion beat were the only variants noted in the more [33] than 9 hours of continuous ECG monitoring.

During the initial portion of the flight, the body-temperature values were unreadable, but they suddenly returned to normal physiologic levels at 01:52 g.e.t. as sown in table 3-X. During the remainder of the flight, the values ranged from 97.7°F to 98.5°F with occasional sudden small changes. These later values are normal, but their accuracy is questionable since proper operation of the system cannot be verified following the period of full-scale readings.

 

Table 3-X.- Inflight Body temperature Values.

Ground elapsed time, hr:mn

Value, °F

00:00 to 01:52

Off scale

01:52 to 02:16

98.5

02:16 to 04:05

98.3 to 98.5

04:05 to 05:24

97.7

05:24 to 09:12

98

 

Postflight

Aeromedical History

 

The astronaut was first seen by a physician 40 minutes after landing and immediately following hatch opening. He appeared active, cheerful, and well coordinated. He egressed from the spacecraft onto the carrier deck requiring no assistance. There was no evidence of deterioration of gait or dizziness at any time following the flight. He expressed great pleasure at the way the flight had gone with such expressions as "I feel fine" and "It was a textbook flight.'' He did not appear unusually fatigued and was eager to talk.

Following, the initial medical examination after recovery, the pilot went to his cabin where he ate a hearty meal. He was still eager to talk and maintained his usual cheerful sense of humor. He retired for the night after a busy day of 21 hours and 40 minutes. After 10 flours of sound sleep, he awoke, urinated, talked, read, and smoked for about an hour. He then returned to bed and slept for 3 additional hours. He appeared well rested and had no apparent residual fatigue from the flight.

 

Physical Examinations

 

The immediate preflight and postflight clinical examinations were accomplished as close together as time permitted in order to maximize detection of any physical changes resulting from the flight. The postflight physical examination and medical debriefing differed from those of previous flights in several important aspects. Since recovery was accomplished in the Pacific Ocean, the entire medical debriefing was carried out aboard the recovery ship, the U.S.S. Kearsarge. The landing of the spacecraft within visibility of the recovery carrier permitted not only an early recovery, but also a very early postflight medical examination of the astronaut by an NASA flight surgeon. For previous missions, it was not possible for a flight surgeon specifically from the NASA and familiar with the pilot's medical history to reach the astronaut so soon.

In less than 1 hour after landing, the physical examination was well underway. Oral temperature was 99.4°F, rectal temperature was 100.1° F, blood pressure (left arm, sitting) was 118/78 mm Hg., and the pulse rate was 92 beats per minute and regular. The pilot's skin was warm and dry but he showed little other evidence of dehydration. His weight loss was only 4 1/2 ±1/4 pounds in spite of the fact that he ate and drank very little during the flight. From the Mercury pressure suit and the urine collection device, 292 cc of urine were recovered, and this sample showed a specific gravity of 1.010.

The specific gravity of his urine rose to 1.018 within a few hours after recovery, and the highest value of 1.021 occurred approximately 12 hours after recovery. The 24-hour period following flight showed a fluid intake of 2,580 cc and a fluid loss of 775 cc. The pilot's hematocrit rose from a preflight value of 44 percent to an immediate postflight Ievel of 47 percent. Twenty-eight hours later, it was 46 percent and dropped to 43 percent in another 24 hours. The laboratory findings are summarized in tables 3-V and 3-VI. These values, coupled with the findings during physical examinations, indicate that dehydration of the astronaut was inconsequential during the flight.

Careful examination of the areas of sensor placement revealed slightly reddened areas resulting from pressure, but no irritation from either tape or electrolyte paste was evident. Two small abrasions were noted over the proximal knuckle of the fifth finger of Astronaut Schirra's right hand. These abrasions were sustained when the plunger of the explosive [34] actuator for the egress hatch recoiled against the pilot's gloved hand, and they occurred in spite of his specific effort to avoid this injury. This ill injury is nearly identical to the one received by Astronaut Glenn during a similar egress from the MA-6 spacecraft. The MR-4 mission was the only other instance where a hatch of the same configuration was actuated. However, no such physical injury was sustained by Astronaut Grissom. Astronaut Schirra also had a reddened area at the shoulders over each acromial process resulting from pressure applied by the couch. This reddening apparently resulted from muscle-tensing exercises conducted during the flight in which he braced his feet on the footboard, his shoulders against the upper portion of the couch, and tensed his back and leg muscles.

A complete physical examination revealed only one finding which is thought to be significant. It was noted that Astronaut Schirra had an increased lability of blood pressure and pulse with changes in body position. When supine, the heart rate averaged about 70 beats per minute, but this value immediately increased to 100 or greater when he stood erect. Blood pressure showed a less dramatic, but still significant, drop in systolic pressure when changing from the supine to the upright position. The reverse was true when he changed position from standing to supine. There was no apparent change in the diastolic pressure.

In addition, it was noted immediately after the flight that all dependent leg veins were engorged. The feet and legs rapidly took on a dusky, reddish-purple color following standing. Astronaut Schirra commented that these color changes were more noticeable than any he had previously observed.

All these findings persisted up to the time the astronaut retired for the night. The next morning, about 21 hours after landing, examination revealed no orthostatic changes.

At no time did the pilot complain of dizziness, lightheadedness, or other symptoms of orthostatic hypotension. He did, however, offer the information that he had felt lightheaded upon egress from the couch in the procedures trainer following 4 hours of lying supine in the Mercury pressure suit under normal gravity conditions. It is impossible with presently available data to isolate the true effect of human exposure to 9 hours of weightlessness as it relates to hemodynamics. This phenomenon will be closely studied in future orbital flights.

The aeromedical debriefing team, composed of the same individuals who conducted the comprehensive medical evaluation prior to flight, examined the pilot 30 flours after landing. In addition to the actual physical examination by physicians, the physical evaluation of the astronaut was based upon an electrocardiogram, an electroencephalogram, chest X-rays and clinical laboratory studies. A summary of the preflight and postflight medical examinations is presented in table 3-IV. Aside from the postflight blood pressure findings and the abrasion on the right hand, all findings were normal.

 

Special Studies

 

The special studies conducted for Mercury flights are nonroutine medical procedures designed to provide information about selected body functions and sensations in the spacecraft environment during flight. These studies for MA-8 comprised biochemical and plasma enzyme determinations and three special measurements.

 

SpeciaI Measurements

 

For the MA-8 mission, the modified caloric test, radiation dosimetry, and retinal photography were the special measurements obtained. One of two modified caloric tests was accomplished 6 days before the flight and the other 2 hours after landing, both by the same physician. Retinal photography and the modified caloric tests revealed no significant changes from the preflight tests. The procedure for the modified caloric test is discussed in detail in reference 8. In addition to the radiation packs (see Scientific Experiments section in paper 1) carried in the spacecraft, three self-indicating dosimeters were placed on the inside of the hatch by the astronaut after launch. Two solid-state lithium fluoride dosimeters were also installed in the helmet liner at eyes level, and three dosimeters of this type were placed on the inside of the underwear, two of which were on the chest and one on the thigh. The self-indicating and solid-state dosimeters revealed that the astronaut's exposure to radiation was insignificant.

 

Biomedical Studies

 

A comparison of the MA-8 biochemical determinations reveals that the astronaut's 9-hour exposure to weightlessness resulted in no biomedical changes which had not been noted after exposure to previous manned orbital flights. Peripheral blood values (table 3-V), including electrolytes, revealed that blood calcium was maximal in the immediate postflight period, but returned to the preflight level within 14 1/2 hours. Such changes, also displayed by the MA-6 and MA-7 pilots, are only suggestive because of their very low magnitude and may have resulted from a number of causes, including dehydration, normal physiologic variation, and laboratory variation. The urinary findings substantiate a minimal dehydration. Intake and output are not discussed since the important inflight urinary output is unknown. The postflight rise in urinary calcium never reached the preflight value, and no abnormality can be established.

 

Plasma Enzyme Studies

 

The number and type of enzyme studies for this mission were modified in order to obtain the maximum amount of useful information from a minimum number of determinations. The results of these determinations are presented in table 3-XI. Many of the postflight values are near or above the normal range for Astronaut Schirra, as well as for astronauts of previous flights. The reason for this elevation in most probably the fact that these individuals are all of a lean body-mass type. Further analysis of the enzyme results, especially heat-stable lactic dehydrogenase, suggests that these postflight elevations are the result of muscular activity rather than the visceral pooling of blood.

 

 

Table 3-XI.- Plasma Enzyme Summary

Normal values

Preflight

Postlanding

- 15 1/2 hr

+ 1 1/2 hr

+ 5 hr

+ 24 1/2 hr

+ 51 hr

Cholesterol, total, mgm/100ml

150 to 240

225

290

270

365

270

Cholesterol esters, percent

60

70

74

70

70

69

Leucylamino peptidase

100 to 310

550

460

530

485

500

Phosphohexose isomerase

10 to 20

28

22

13

23

21

Lactic dehydrogenase

150 to 250

Incubated, 20° to 25°C

-

250

225

200

275

250

Heat stable, 60°C

-

60

75

35

75

75

Heat stable, percent

14 to 15

24

33

33

27

30

Malic dehydrogenase

-

275

325

225

300

325

 

Conclusions

 

1. There was no evidence of disorientation or related untoward symptoms during the 9-hour period of weightlessness. The inflight orientation test demonstrated no impairment of performance during this weightless period.

2. An orthostatic rise in heart rate, fall in systolic blood pressure, and maintenance of diastolic pressure was noted during the 24 hours immediately after landing. Such a hemodynamic phenomenon may have more serious implications for a longer mission. A prescribed inflight exercise program may be necessary to preclude symptoms in case of the need for an emergency egress soon after landing.

3. Lability of instantaneous heart rate was not associated with respiration of other known physical activity. The cause of this phenomenon is unknown.

4. There were no significant medical abnormalities, other than those previously mentioned, during or following the mission.

5. The radiation exposure was minimal and posed no hazard to flight.

6. There are no medical contraindications to embarking on a longer mission.

Acknowledgments. The contributions of the following individuals were most helpful in the preparation of this paper: A. Duane Catterson, M.D., David P.Morris, M.D., Robie Hackworth, and Nelson Parsons, Aerospace Medical [36] Operations Office, NASA Manned Spacecraft Center; Richard D. Hansen, M.D., U.S: Air Force Academy, Colorado; Donal Flinn, M.D., and W. Bruce Clark, M.D., USAF School of Aerospace Medecine, San Antonio, Texas: Ashton Graybiel, M.D., USN School of Aviation Medecine, Pensacola, Florida; Edward C.Knoblock, Ph.D., and Joseph Kelly, Walter Reed Army Institute of Research, Washington, D.C.; Charles C. Watts, Jr., M.D., and S/Sgt. Carlton L. Stewart, Lackland Air Force Hospital, San Antonio, Texa; Max J. Trummer, M.D., Philadelphia, Pennsylvania; Frank L. Mahan, M.D., Fort Worth, Texas; Walter Frajola, Ph.D., Ohio State University; and the staff of the Armed Forces Institute of Pathology.

The following flight controllers are also acknowledged, without whom there would be no summary: Roy J.Kelly, M.D., USAF; Howard R. Unger, M.D., USAF; Robert R. Burwell, M.D., USAF; Clyde H.Kratochvil, M.D., USAF; Warren J. Bishop, M.D., RAAF; Jacques L.Sherman, Jr., M.D.,USA; John C.Lane, M.D., Melbourne, Australia; William H.Shea, M.D., USAF; Edward L. Beckman, M.D., USN; Robert H. Moser, M.D., USA; William L.Hall, M.D., USN; George G.Luchinna, M.D., USN; Laurence H. Blackburn, Jr., M.D., USN; Duane E. Graveline, M.D., USAF; and Paul W. Musgrave, M.D., USAF.


References

 

1. JACKSON, CARMAULT B., JR., DOUGLAS, WILLIAMS K. et al.: Results of Preflight and Postfight Medical Examinations. Proc. Conf. on Results of the First U.S. Manned Suborbital Space Flight. NASA, Nat. Inst. Health, and Nat. Acad. Sci., June 6, 1961, pp. 31-36.

2. AUGERSON, WILLIAM S., and LAUGHLIN, C. PATRICK: Physiological Responses Of the Astronaut to the MR-3 Flight. Proc. Conf. on Results of the First U.S. Manned Suborbital Space Flight. NASA, Nat. Inst. Health, and Nat. Acad. Sci., June 6, 1961, pp. 45-50.

3. DOUGLAS, WILLIAM K., JACKSON, CARMAULT B., JR., et al.: Results of the MR-4 Prefight and Postflight Medical Examination Conducted on Astronaut Virgil l. Grissom. Results of the Second U.S. Manned Suborbital Space Flight, July 21, 1961. Supt. Doc., U.S. Government Printing Office (Washington, D.C.), pp. 9-14.

4. LAUGHLIN, C. PATRICK, and AUGERSON, WILLIAM S.: Physiological Responses of the Astronaut in the MR-4 Space Flight. Results of the Second U.S. Manned Suborbital Space Flight, July 21, 1961. Supt. Doc., U.S. Government Printing Office (Washington, D.C.), pp 15-21.

5. DOUGLAS, WILLIAM K.: Flight Surgeon's Report for Mercury-Redstone Missions 3 and 4. Results of the Second U.S. Manned Suborbital Space Flight, July 21, 1961. Supt. Doc., U.S. Government Printing Office (Washington, D.C.), pp. 23-31.

6. MINNERS, HOWARD A., DOUGLAS, WILLIAM K., et al.: Aeromedical Preparation and Results of Postflight Medical Examinations. Results of the First United States Manned Orbital Space Flight, Febuary 20, 1962. Supt. Doc., U.S. Government Printing Office (Washington, D.C.), pp. 83-92.

7. LAUGHLIN, C. PATRICK, McCUTCHEON, ERNEST P., et al.: Physiological Responses of the Astronaut. Results of the First United States Manned Orbital Space Flight, February 20, 1962. Supt. Doc., U.S. Government Printing Office (Washington, D.C.), pp. 93-103.

8. MINNERS, HOWARD A., WHITE, STANLEY C., et al.: Clinical Medical Observations. Results of the Second United States Manned Orbital Space Flight, May 24, 1962. NASA SP-6, Supt. Doc., U.S. Government Printing Office (Washington, D.C.), pp. 43-53.

9. McCUTCHEON, ERNEST P., BERRY, CHARLES A., et al.: Physiolopical Responses of the Astronaut. Results of the Second United States Manned Orbital Space Flight, May 24, 1962. NASA SP-6, Supt. Doc., U.S. Government Printing Office (Washington, D.C.), pp. 54-62.

 


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