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MERCURY PROJECT SUMMARY (NASA SP-45)

 

18. AEROMEDICAL OBSERVATIONS

 

By A. D.CATTERSON, M.D., Center Medical Operations Office, NASA Manned Spacecraft Center; E.P. McCUTCHEON,1 M.D., Center Medical Operations Office, NASA Manned Spacecraft Center; H. A. MINNERS, M.D., Center Medical Operations Office, NASA Manned Spacecraft Center; and R. A. POLLARD, M.D., Center Medical Operations Office, NASA Manned Spacecraft Center

 

Summary

 

[299] The results of physiologic measurements and medical studies of Astronaut Cooper made prior to, during, and following his flight as pilot of the spacecraft of the MA-9 mission are presented in this paper. The pilot was in excellent health and in a complete state of mental and physical fitness for his mission on launch morning. The data revealed that all physiologic parameters measured in flight remained within the envelope of normal variability developed for this pilot through extensive monitoring of these same parameters under dynamic circumstances during his participation in training activities as a Mercury astronaut.

 

Astronaut Cooper withstood the stresses of flight situation with no evidence of degradation of his functional integrity as a pilot. He slept as part of the planned mission activities during his flight and reported that sleep was subjectively normal. Postflight examination of Astronaut Cooper revealed that he had developed dehydration. He exhibited an orthostatic hypotension accompanied by an accelerated pulse response in the postflight examinations. The pulse and blood pressure responses returned to normal while the pilot was sleeping between 9 hours and 19 hours after landing. A reversal of the ratio between neutrophiles and lymphocytes was noted in the peripheral blood at an examination accomplished 4 days after the mission. This lymphocytosis persisted for 2 weeks and subsided spontaneously by June 14, 1963. With respect to all other studies, the medical status of the pilot was found essentially unchanged between the preflight and postflight examinations.

 

This paper presents the specific results of medical studies of Astronaut Cooper's responses during and after his MA-9 mission in the dual context of a detailed report of the final Mercury mission and an effective summary in its own right of the-medical findings from Project Mercury. The results of the MA-9 mission are an effective summary of the entire program because every observation which was made on pilots during the earlier missions was repeated and qualitatively reconfirmed in the final flight.

 

At the same time, the medical-data collection program for the last flight was developed on the foundation of knowledge gained from each of the preceding manned space missions. The suitability and the limitations of the Mercury spacecraft environment to meet the requirements of human physiology were better understood with each succeeding flight. Thus, the final flight was approached with a better understanding of the likelihood of a given physiologic response occurring after exposure to the known stresses of a mission profile than had been previously possible. The opportunity for making valid medical observations during the MA-9 mission was further enhanced by the duration of the mission, as well as by the length of participation of Astronaut Cooper in the Mercury program, which provided an invaluable fund of baseline data prior to his actual flight.

 

Preflight Observation

 

Data were evaluated from very thorough medical studies of the pilot, Astronaut L. Gordon Cooper, Jr., conducted immediately prior to his selection for astronaut training in 1959 and from annual examinations since that [300] date. Medical examinations were also conducted both before and after six preflight spacecraft checkout tests and a session in the Cape Canaveral procedures trainer, all of which required the pilot to wear the full-pressure space suit. Special examinations to assess the pilot's fitness for flight were conducted 11 and 3 days before launch. The latter examination conducted on May 12,1963, designated the "Comprehensive Medical Evaluation," was conducted by specialists in internal medicine, Ophthalmology, neuropsychiatry, radiology, and aviation medicine. The NASA flight surgeon who had examined the pilot for most of the preflight activities conducted the final preflight medical examination on launch morning. The preflight aeromedical procedures and examination are listed in table 18-I.

 


Table 18-I. Pilot Preflight Activities

[Selected activities for which medical study or support was performed]

Date

Activity

Medical study or support

January 5

Altitude-chamber spacecraft checkout.

Physical examination before and after.

Background data (biosensors).

March 22-23

Hangar flight simulation.

Physical examination before and after.

Background data (biosensors).

April 23

Flight simulation no.1

Physical examination.

Background data (biosensors).

Timed urine collection.

May 4

T-10 day physical examination.

Physical examination, 45 minutes.

May 7

Mission simulation (procedures trainer)

Physical examination before and after.

Background data (biosensors).

Timed urine collection.

May 8

Launch simulation.

Physical examination before and after.

Background data (biosensors).

Timed urine collection.

Begin controlled diet.

Blood specimen, 50cc

May 10

Flight simulation no.3.

Physical examination before and after.

Timed urine collection.

Background data (biosensors).

May 11

-

Begin low residue diet.

May 12

T-2 day physical examination.

Comprehensive medical examination, 2 1/2 hours

Blood (30cc) and urine specimen.

May 14

Countdown (flight canceled).

Physical examination before and after.

Blood specimen, 30cc

Timed urine collection.

May 15

Flight countdown.

Physical examination

Aeromedical countdown

Awaken 2:51 a.m. e.s.t.

Launch 8:40 a.m. e.s.t.


 

In addition to examinations by physicians, baseline clinical evaluations included an audiogram, an electrocardiogram, a chest X-ray, and laboratory studies of blood and urine. The results of these evaluations are found in tables 18-II to 18-V. For the 3 months prior to the flight, the pilot continued in excellent health with no significant abnormalities. In the month prior to flight, he maintained his physical fitness by daily distance running and calisthenics.

 

Close supervision of the pilot's food intake began 7 days before the planned flight with special preparation of a normal balanced diet. In order to reduce the need for defecation during the mission, a low-residue diet was followed for 4 days before the launch (ref. l). This diet was well tolerated, although the pilot did mention that appetite satisfaction was short-lived following the low-residue meals.


[301] Table 18-II. Pertinent excerpts from clinical examination

Preflight, May 15, 1963;

3:55 to 4:11 a.m. e.s.t.

Postflight (U.S.S. Kearsarge) May 16, 1963;

7:15 to 7:45 p.m. e.s.t

Temperature (oral), °F

97.4

99.4

Hear rate, beats/min

76

86

Respiration rate, breaths/min

16

16

Blood pressure, left arm, mm Hg

108/76 supine

122/82 standing

90/80 supine

Nude weight (bladder empty), lb

147

139 1/4

Comments

Alert, cooperative, 2+ erythema at BPMS microphone tape site.

Fatigued and sweating. See text.



Table 18-III. Complete Blood Count. (all times are in e.s.t)

Sept.4, 1959

Mar 4, 1963; 1:40 p.m.

May 12, 1963; 5:00 p.m.

May 16, 1963; 8:55 p.m.

May 17, 1963; 9:00 p.m.

May 20, 1963; 11:00 a.m.

May 31, 1963; 3:00 p.m.

June 14, 1963

Hematocrit, percent

46

44

43

49

43

43

43

43

Hemoglobin, grams/100 ml

14.8

14.3

15.0

16.5

14.0

14.7

14.3

14.2

Red blood cells, millions/mm3

5.09

-

4.79

4.80

4.83

4.50

-

-

Platelets/mm3

-

284,000

314,000

-

-

230,000

-

-

White blood cells/mm3

5,850

6,800

6,500

9,200

5,650

6,000

7,700

5,100

Differential blood count:

Neutrophiles, percent

69

50

60

75

49

35

38

49

Lymphocytes, percent

29

46

36

20

42

58

61

47

Monocytes, percent

1

2

3

5

5

5

1

2

Eosinophiles, percent

0

2

1

0

3

2

0

1

Basophiles, percent

1

0

0

0

1

0

0

1



Table 18-IV. Comparison of typical preflight and postflight urine values.

Preflight

Postflight

Date, 1963

May 12

May 20

Source

Random sample

Random sample

Specific gravity

1.1018

1.1019

pH

6.0

6.0

Albumen, sugar, acetone, and bile

Negative

Negative

Microscopic

Few WBC, no RBC, small amounts of amorphous phosphates and mucus, and one hyaline cast.

One to 2 WBC/HPF, no RBC, no casts, moderate amount of amorphous phosphates.



[302-303] Table 18-V. Urine Analysis.

Date

Time

Total volume, cc

Specific gravity

Na, mEq/l

K, mEq/l

Ca, mEq/l

Cl, mEq/l

PO4, mg%

Creatinine, mg%

Comments

Mar. 20, 1963

7:30 a.m. to 9:26 a.m.

184

1.012

141

55

4.15

161

26.7

85

Low residue diet

Mar. 20, 1963

9:26 a.m. to 12:59 a.m.

260

1.013

180

49

16.3

207

42.2

110

-

Mar. 20, 1963

12:59 a.m. to 4:45 p.m.

420

1.014

129

40

10.1

159

56.6

86

-

Mar. 20, 1963

4:45 p.m. to 9:10 p.m.

330

1.015

125

38

8.7

111

73

111

-

Mar. 21, 1963

9:10 p.m. to 1:00 a.m.

340

1.012

137

17

7.5

100

58.3

102

-

Mar. 21, 1963

1:00 a.m. to 7:52 a.m.

830

1.005

79

14

5.0

79

31.4

62

-

Mar. 21, 1963

7:52 a.m. to 12:46 p.m.

470

1.011

143

42

10.3

174

26.6

94

-

Mar. 21, 1963

12:46 p.m. to 5:28 p.m.

286

1.017

179

54

16.85

210

74.3

125

-

Mar. 21, 1963

5:28 p.m. to 11:35 p.m.

600

1.015

189

41

7.6

178

48

105

-

Mar. 22, 1963

11:35 p.m. to 3:26 a.m.

210

1.015

239

31

10.6

163

54

-

-

Mar. 22, 1963

3:26 a.m. to 5:36 a.m.

110

1.018

216

34

25.5

165

55

-

-

Mar. 22, 1963

5:36 a.m. to 10:47 a.m.

255

1.018

154

38

21.3

142

54

134

-

Mar. 22, 1963

10:47 a.m. to 6:35 p.m.

300

1.020

116

47

20.85

86

135

152

Before hangar simulated flight.

Mar. 23, 1963

6:35 p.m. to 1:20 a.m.

360

1.023

131

51

18.9

119

75.4

142

During hangar simulated flight.

Apr. 23, 1963

6:00 a.m. to 6:50 a.m.

32

-

196

58

7.75

158

146

144

Simulated flight no.1 (before)

Apr. 23, 1963

6:50 a.m. to 12:35 p.m.

394

1.020

226

85

3.04

220

70.8

106

Simulated flight no.1 (during)

Apr. 23, 1963

12:35 p.m. to 5:08 p.m.

122

1.022

195

51

5.95

187

68.6

98

Simulated flight no.1 (after)

Apr. 25, 1963

Unknown to 11:35 a.m.

170

1.020

192

83

6.3

212

18.7

107

Simulated flight no.2 (before)

Apr. 25, 1963

11:35 a.m. to 4:28 p.m.

134

1.024

242

40

5.75

226

35.4

104

Simulated flight no.2 (during)

Apr. 25, 1963

4:28 p.m. to 5:55 p.m.

308

1.018

250

44

3.40

234

46.1

107

Simulated flight no.2 (after)

May 7, 1963

6:30 a.m. to 8:30 a.m.

64

1.020

115

56

13.9

198

103

152

Procedures trainer (before).

May 7, 1963

8:30 a.m. to 2:00 p.m.

480

1.014

124

60

5.65

146

63.6

88

Procedures trainer (during).

May 8, 1963

9:15 a.m. to 1:40 p.m.

540

1.012

137

79

7.4

166

41.6

74

Launch simulation (during).

May 8, 1963

1:40 p.m. to 6:00 p.m.

360

1.012

137

53

3.2

125

43

104

Launch simulation (after).

May 10, 1963

7:30 a.m. to 11:45 a.m.

180

1.023

148

85

17.8

176

45.7

130

Simulated flight no.3 (before)

May 10, 1963

11:45 a.m. to 2:00 p.m.

170

1.025

198

72

20.7

219

76

114

Simulated flight no.3 (before)

May 10, 1963

2:00 p.m. to 6:30 p.m.

320

1.023

181

83

13.4

201

97

115

Simulated flight no.3 (during)

May 10, 1963

6:30 p.m. to 10:05 p.m.

80

1.026

200

71

6.9

165

148

139

Simulated flight no.3 (after)

May 13, 1963

6:30 p.m. to 9:00 p.m.

440

1.025

177

54

19.95

165

128

137

Before canceled flight.

May 14, 1963

9:00 p.m. to 2:50 a.m.

225

1.024

165

32

10.0

107

161

152

Before canceled flight.

May 14, 1963

2:50 a.m. to 7:30 a.m.

680

1.012

120

49

5.6

128

12.6

56

Collection device-canceled flight.

May 14, 1963

7:30 a.m. to 12:30 p.m.

315

1.015

98

50

5.85

109

34

104

After canceled flight.

May 15, 1963

10:00 p.m. to 2:52 a.m.

178

1.028

112

34

23.4

73

214

162

Preflight.

May 15, 1963

2:52 a.m. to 3:55 a.m.

25

1.025

98

48

12.4

89

185

165

Preflight.

May 15, 1963

3:55 a.m. to 7:56 a.m.

177

-

184

68

8.25

212

33.8

125

Preflight (pad) bag no.1

May 15, 1963

7:56 a.m. to 12:29 p.m.

195

-

213

69

14.1

236

28.4

131

Inflight bag no.2

May 15, 1963

12:29 p.m. to 10:09 p.m.

314

-

197

56

12.6

188

130

154

Inflight bag no.3

May 16, 1963

10:09 p.m. to 7:15 a.m.

333

-

120

38

17.7

128

125

169

Inflight bag no.4

May 16, 1963

7:15 a.m. to 1:14 p.m.

107

1.026

137

41

15.6

150

136

170.8

Collection device.

May 16, 1963

1:14 p.m. to 9:30 p.m.

70

1.031

107

96

16.4

126

240

177

1st voided sample.

May 17, 1963

9:30 p.m. to 1:05 p.m.

475

1.026

41

62

20.95

29

149

148

2nd voided sample.

May 17, 1963

1:05 p.m. to 9:12 p.m.

315

1.020

29

54

24.3

59

68.5

148

3rd voided sample.

May 18, 1963

9:12 p.m. to 12:00 p.m.

605

1.023

29

70

17.4

41

114

139

4th voided sample.

May 20, 1963

8:00 a.m. to 10:15 a.m.

-

1.019

125

92

15.2

150

68

110

4 days after recovery (physical exam Patrick AFB)


 

[304] The results of the final prelaunch examination revealed a healthy pilot who was ready for the mission. Two minor discrepancies were local skin erythema at the biosensor sites and moderate erythema, edema, and tenderness of the skin over the right sacral prominence. He frequently demonstrates a skin reaction around the sensors for 24 to 36 hours after application, despite the use of microporous surgical tape for fastening these sensors. It should be noted that these sensors were in place for 7 hours during the canceled launch on the preceding day. The skin findings over the sacrum are frequently present following prolonged periods of 4 or more hours on his back in the couch.

 

On the night before the postponed launch of May 14, 1963, the pilot slept well for about 2 hours and then dozed restlessly for another 3 1/2 hours. However, on the night before the successful launch, he slept well for 6 hours. Although he did become sleepy during periods of relative inactivity, such as the period spent in the transfer van, he felt adequately rested on launch morning. At no time was a drug administered to induce sleep.

 

The sources of detailed preflight physiologic data are outlined in tables 18-VI to 18-IX. These sources include dynamic tests for evaluation of general physical condition, Mercury Atlas three-orbital pass simulations, and Mercury-Atlas acceleration profiles conducted at the U.S. Naval Aviation Medical Acceleration Laboratory (AMAL) in Johnsville, Pa., and various spacecraft checkout procedures required during the final stages of preparation for flight.

 

The procedures which were monitored resulted in the largest number of total hours of observation yet available for any one astronaut. This extensive monitoring, was possible as a result of his activity as the MA-8 backup pilot and of his participation in three altitude-chamber spacecraft-checkout procedures, including the longest such test conducted at Cape Canaveral.

 

The pilot-safety monitoring and data-gathering biosensor system for this mission consisted of two sets of electrocardiographic (ECG) leads, the impedance pneumograph, an oral temperature thermistor, and the blood-pressure measuring system (BPMS). The details of operation of the biosensor system have been described in references 1 to 3. Because of the increased duration of the MA-9 flight, a change was made from continuous rectal to intermittent oral body temperature measurement. The basic thermistor was retained. The thermistor and its lead wires remained within the suit. The sensor was attached to the right ear muff inside the helmet where it was readily accessible The sensor and its location are illustrated in figures 18-1 and 18-2. It thereby provided an indication of suit-outlet temperature whenever an oral temperature was not being taken. When oral temperature was desired, the pilot placed the small thermistor under his tongue for about 5 minutes. Preflight body temperatures were all within the normal range. The remainder of the biosensor system was the same as that used for the MA-8 mission (ref. 1).


Photo of oral temperature probe

Figure 18-1. Oral temperature probe.


photo of temperature probe located inside space helmut

Figure 18-2. Installation of oral temperature probe in helmet.

 

Preflight biosensor preparation included careful calibration of the system so that accurate, repeatable determinations were assured . Adjustments were required to compensate for individual variations. This requirement was especially true for the blood-pressure measuring system. The clinical blood-pressure mean

 


[305] Table 18-VI. Detailed preflight heart-rate and respiration-rate data.

Date

Procedure

Duration of observation, hr:min

Mean

Heart rate

Respiration rate

Heart rate, beats/min

Respiration rate, breaths/min

Number of values

±2 standard deviations, beats/min

Range

Number of values

±2 standard deviations, breaths/min

Range

Minimum

Maximum

Minimum

Maximum

February 1959

Lovelace Clinic exercise tolerance test.

a 0:14

-

-

(b)

-

-

185

(b)

-

-

-

Sept.28, 1961, and Mar. 28, 1963

Mercury-Atlas Centrifuge dynamic simulations.

4:18

83

(b)

177

57 to 109

58

151

(b)

-

-

-

Apr. 13, 1962

Altitude chamber spacecraft checkout

10:29

79

18

161

54 to 104

60

129

117

11 to 25

12

28

July 23, 1962

Altitude chamber spacecraft checkout

7:33

64

19

111

49 to 79

46

92

111

14 to 24

13

26

Jan. 5, 1963

Altitude chamber spacecraft checkout

6:17

74

17

20,000

56 to 92

56

102

123

10 to 24

10

26

Mar. 23, 1963

Hangar flight simulation

2:00

64

19

4,254

51 to 77

55

106

44

8 to 30

13

41

Apr. 23, 1963

Flight simulation no.1

3:40

71

19

75

56 to 86

51

92

75

14 to 24

13

28

May 7, 1963

Mission simulation (procedures trainer).

5:22

71

(b)

103

50 to 92

50

102

(b)

-

-

-

May 8, 1963

Launch simulation

4:48

72

20

17,232

54 to 90

52

107

94

13 to 27

11

28

May 10, 1963

Flight simulation No.3

3:30

62

19

67

39 to 85

48

96

67

13 to 25

10

26

May 14, 1963

Launch countdown (canceled)

5:41

71

20

19,666

53 to 89

47

132

96

14 to 26

14

30

May 15, 1963

Launch countdown

2:31

73

16

9,010

48 to 98

51

104

50

10 to 22

10

24

a Duration determined by the maximum heart rate.

b Not recorded.



[306] Table 18- VII. Summary of Hear-rate and respiration-rate data.

 

Preflight

Date

Procedure

Duration of observation, hr:min

Overall mean

Range of mean rates

Range of ±2 standard deviations

Heart rate, beats/min

Respiration rate, breaths/min

Heart rate, beats/min

Respiration rate, breaths/min

Heart rate, beats/min

Respiration rate, breaths/min

September 1961 to May 15, 1963.

Centrifuge simulations and checkout procedures

56:23

72

19

62 to 83

16 to 20

39 to 104

8 to 30

Inflight

Date

Procedure

Duration of observation, hr:min

Mean

Heart rate

Respiration rate

Heart rate, beats/min

Respiration rate, breaths/min

Number of values

±2 standard deviations, beats/min

Range, beats/min

Number of values

±2 standard deviations, beats/min

Range, beats/min

May 15 and May 16, 1963.

Orbital flight

34:16

89

15

76,174

62 to 116

55 to 180

151

5 to 25

6 to 28

Postflight

May 16 and May 17, 1963.

Physical examinations.

(a)

77

16

4

72 to 82

56 to 88

1

(b)

-

a Not determined, not time critical.
b Not applicable.



[307] Table 18-VIII. Detailed preflight blood-pressure data.

 

Date

Procedure

Duration

Mean blood pressure, mm Hg

Systole

Diastole

Mean pulse pressure, mm Hg

Number of values

Range, mm Hg

Number of values

Range, mm Hg

Preflight, clinical

February 1959

Lovelace Clinic exercise tolerance test

00:14

a 174/86

-

-

-

-

-

March 1959

Aeronautical Systems Division dynamic tests:

Cold pressor

(b)

105/74

13

100 to 112

13

70 to 82

31

Tilt

(b)

109/75

30

92 to 138

30

68 to 88

34

Treadmill

(b)

134/87

18

110 to 156

18

80 to 100

47

September 1959

Lackland USAF Hospital physical examination

(b)

113/70

4

110 to 116

4

68 to 72

42

April 1962

Physical examinations

(b)

100/80

5

88 to 108

5

72 to 88

20

July 1962

Special BPMS test

(b)

116/78

58

102 to 124

58

64 to 84

39

July 23, 1962

Physical examinations

(b)

103/79

16

98 to 106

16

73 to 82

25

March 12, 1963

Physical examinations

(b)

108/72

4

98 to 118

4

68 to 78

37

Apr. 23, 1963 to May 15, 1963

Physical examinations during final preflight checkout period.

(b)

115/78

8

105 to 120

8

72 to 82

37

Preflight, blood pressure measuring system.

Sept. 12, 1961

Mercury-Atlas centrifuge dynamic simulation

2:23

114/85

12

103 to 144

12

66 to 98

29

Apr. 13, 1962

Altitude-chamber spacecraft checkout

10:29

134/91

10

128 to 148

10

70 to 124

43

July 10 and July 23, 1962

BPMS calibration

3:00

110/79

73

96 to 128

69

63 to 88

31

July 23, 1962

Altitude-chamber spacecraft checkout

7:33

94/71

8

79 to 111

8

61 to 79

23

Jan. 3, 1963

BPMS calibration

1:00

108/80

14

99 to 116

14

73 to 87

28

Jan. 5, 1963

Altitude-chamber spacecraft checkout

6:17

112/83

12

99 to 122

12

77 to 89

29

Mar. 22 and Mar. 23, 1963

Hangar flight simulation

2:05

94/71

5

89 to 107

5

65 to 81

23

Apr. 23, 1963

Flight simulation No.1

3:40

114/91

6

104 to 123

6

81 to 99

23

May 8, 1963

Launch simulation

4:48

106/82

12

101 to 123

12

71 to 91

24

May 10, 1963

Flight simulation No.3

3:30

110/90

2

107 to 112

2

89 to 91

20

May 14, 1963

Launch countdown (canceled)

5:41

120/82

8

117 to 127

8

77 to 89

38

May 15, 1963

Launch countdown

2:31

110/82

4

107 to 119

4

73 to 89

28

a Value at test endpoint, other values not available.
b Not determined, not time critical.



[308] Table 18-IX. Summary of Blood pressure data.

Date

Procedure

Duration, hr:mn

Mean blood pressure, mm Hg

Systole

Diastole

Mean pulse pressure, mm Hg

Number of values

±2 standard deviation, mm Hg

Range, mm Hg

Number of values

±2 standard deviation, mm Hg

Range, mm Hg

Preflight clinical

February 1959 to May 15, 1963

Crew selection examination, special tests and preflight examinations.

(a)

113/79

95

99 to 127

88 to 124

95

69 to 89

64 to 88

34

Preflight, blood pressure measuring system

September 1961 to May 15, 1963

Centrifuge simulations and preflight test procedures

56:09

112/79

160

86 to 138

79 to 148

160

58 to 90

61 to 124

33

Inflight, blood pressure measuring system

May 15 and May 16, 1963

Orbital flight

34:16

119/81

12

(b)

109 to 131

12

(b)

73 to 89

38

Postflight, clinical

May 16 and May 17, 1963

Postflight physical examinations.

(a)

91/66

16

75 to 107

86 to 100

16

55 to 77

52 to 82

25

a Not determined, not time critical.
b Not applicable.


 

[309] values, shown in table 18-IX, are of particular interest and indicate that the correlation between these readings and those taken with the BPMS is valid. The stability of these calibrations was rechecked on several occasions before flight. All systems operated properly during the final preflight-preparation period.

 

The preflight biosensor data are presented in tables 18-VI to 18-IX. The analysis methods used were both manual and automatic.

 

All respiration minute rates were obtained by manual reduction; 30- second counts made from the continuous direct-recorded analog signal, with sampling intervals either every 3 or every 4 minutes. Heart rates from many of the records were determined in the same manner. Those sets can be readily identified by the relatively low number of values used. The automatic analysis utilizes a general-purpose computer to determine the intervals between all the R waves of the ECG complex in the record, and the reported values were computed from these determinations. The automatically reduced rates are readily identified by the large number of values. The validity of both of these methods has been substantiated by repeated cross- correlation of results during the two years of development of the analysis program. Although the data analysis format was arbitrarily selected, the results are fully reproducible and appear to be adequate for the present medical requirements. All blood-pressure measurements on record were incorporated in the tables.

 

A highly significant aspect of the preflight data is the rather wide range of values recorded, particularly heart rates, which have modified the understanding of expected or so called "normal" responses. This wide variation is a common phenomenon among healthy individuals in dynamic situations, and clearly indicates the need for the use of extreme caution in attributing changes observed in flight to weightlessness or other factors peculiar to the flight environment.

 

The ECG from the preflight observation period was scanned repeatedly by numerous observers The collective opinions were that marked normal sinus arrhythmia was present with frequent occurrences of a wandering cardiac pacemaker. At times, sinus node suppression was sufficient to allow activation by the atrio-ventricular (A-V) node with escape and fusion beats. This occurrence was identified by both biphasic and negative P waves of decreased amplitude, and on occasion by changes in the ventricular complexes. Numerous such beats were noted during the countdown of the postponed launch, and one brief episode of nodal rhythm occurred during this period. This finding was considered acceptable as a normal variant in this pilot only by virtue of the extensive preflight monitoring which had shown nodal rhythm to be an incidental occurrence. These data are illustrated in figure 18-3. There was sinus bradycardia, which, at times, was followed by a sinus-generated beat and, at other times, was followed by an A-V nodal-generated escape beat. Other infrequent rhythm alterations were premature atrial and ventricular beats. The preflight data were collected in order to establish the baseline physiological responses of the MA-9 astronaut specifically using the flight biomedical instrumentation.

 

FLIGHT OBSERVATIONS

 

Inflight biomedical monitoring spanned a time interval of 34 hours, 16 minutes, and 43 seconds on this flight. Continuous onboard recording included the first 1 hour and 35 minutes and the last 10 hours and 45 minutes of flight time until bioplug disconnect. Flight data were programed to be intermittently recorded for 1 minute of every 10 minutes between 1 hour and 39 minutes elapsed time and 23 hours and 32 minutes elapsed time. Recording of physiological data through the mid-portion of the flight was erratic and did not follow original plans because of a malfunction of the tape-recorder programer which occurred at approximately 12:00:00 ground elapsed time (g.e.t.) and continued throughout the flight. However, sufficient data points were obtained for confident extrapolation of trends of physiologic values during this portion of the flight by the astronaut's voice contacts with the ground, his use of the vox-record actuation of the tape recorder, or his turning the tape recorder temporarily to continuous to document certain inflight experiments. Data during the final portion of the flight, from 24:00:00 g.e.t. until landing, were obtained because the failed programer was over

 


[
310] Figure 18-3. May 14, 1963, 07:42:00 e.s.t. Sample record illustrating nodal beats occurring during canceled launch countdown. Recorder speed 25mm/sec.

 

ridden by the astronaut's selection of continuous recorder operation During the period when the astronaut was resting quietly or was asleep, essentially no medical data were obtained on the onboard recorder; consequently mean heart-rate values for the entire duration of the flight are probably biased on the high side of a true mean. Data from the onboard recorder have been supplemented by data obtained during network station passes throughout the mission, and an exceptionally valuable short period of recording was obtained onboard the carrier during egress of the astronaut. The inflight responses are summarized in tables 18-VII and 18-IX. Heart-rate response, including mean rates, was obtained through a computer reduction of the inflight data from the onboard tape recorder.

 

Respiration rates were obtained by the manual reduction of 30-second periods every 3 minutes during the period of continuous recording and from 30-second averages taken at all other short intervals when data were available from the onboard tape recorder. Blood pressures were obtained according to the flight plan with only very minor variations. These values were with few exceptions not recorded on the onboard recorder since the astronaut was generally quiet while sending the blood pressure, and therefore the tape recorder was not operating. However, the values were received at ground stations in every instance and read in real time by medical monitors. The readings were subsequently verified by postflight analysis of the tracking-site data. Body temperature was sampled intermittently during the flight with an oral thermistor, which the pilot placed under his tongue on four of the five planned occasions. One additional oral temperature was requested and obtained during the flight. Body temperatures obtained in flight and listed in table 18-X were all within an acceptable range.

 


[311] Table 18-X. Oral Temperatures Obtained in Flight.

Ground elapsed time, hr:min:sec

Oral temperature, °F

1:10:00

98.8

6:00:00

100.0

10:25:00

100.0

12:25:00

99.0

23:50:00

98.0


 

The overall mean heart rate recorded during the period when the inflight recorder was operative was 89 beats pet minute, and the overall respiratory rate recorded from available data was 19 breaths per minute. The significant events of powered flight showed corresponding increases in heart rate and respiratory rate, as has been the case in all manned Mercury flights. The pilot's heart rate at booster-engine cut-off (BECO) was 147 beats per minute; at launch-escape-rocket ignition, 154 beats per minute; and at sustainer-engine cut-off (SECO), 144 beats per minute. Within 2 minutes after SECO, the heart rate subsided to about 110 beats per minute and then gradually declined over the next 1.3 minutes to rates of 80 to 100 beats per minute for the remainder of the first orbital pass. Respiratory rate was 28 breaths per minute at BECO, between 25 and 30 breaths per minute through SECO, and then declined to rates of 18 to 20 breaths per minute within the first 15 minutes of weightless flight.

 

Heart rate remained stable around 80 beats per minute throughout the first 8 flours in space except during periods when the astronaut announced on the tape that he was undergoing some specific exertion such as emptying the condensate tank or removing equipment from the equipment kit. During these intervals' rates would increase to values from 100 beats per minute to as high as 130 beats per minute for very short times.

 

At 8:25:00 g.e.t., the pilot specifically mentionned struggling with his writing desk. At this time, his heart rate rose to 96 beats per minute and then promptly settled back to its resting rate of about 80. The longer period of observation and the opportunity which this flight afforded to correlate pilot activities with heart and respiratory rates permit a tentative appraisal of the effect on these rates of exertion under equally cramped circumstances at 1g. There does not appear to be a significant difference in terms of heart-rate and respiratory-rate response in the two situations. This impression was further borne out in the two planned exercise periods in which there was similarity between the response to exercise in orbital flight and the response to exercise in preflight practice sessions, as shown in table 18- XI.

 

When the flashing light was deployed at about 3:26:00 g.e.t. his heart rate rose to a sharp peak of 134 beats per minute and then promptly declined to 90 beats per minute while the pilot was maneuvering the spacecraft in an attempt to sight the flashing light.

 

The respiratory rate sensor malfunctioned during the flight. The failure was subsequently traced to a separation of the lead wire from the electrode, which was attached to the left lower chest. The first sign of respiration-sensor failure occurred at 7:08:00 g.e.t.; and throughout the remainder of the flight,, the respiratory rate recording was intermittent. Sometimes, the trace appeared to be a faithful replica of the pilot's breathing, but at other times it was entirely unreliable or without apparent relation - ship to respiration. The respiratory rates during the last portion of the flight are tentative rates based on the appearance of the pneumograph waveform during periods when evidence available indicated it was following changes in thoracic volume. Typical signals of properly operating biosensors are illustrated in figure 18-4.

 

During the sleeping period, heart rates recorded on passes over tracking stations were generally as low as 50 and averaged between 55 and 60 beats per minute. However, when the pilot awoke and announced anything which was recorded on the onboard recorder, his heart rate immediately rose to about 80 which is the same value as during his working period earlier in the flight. After about 23:32:00 g.e.t. and for the remainder of the normal orbital flight, the astronaut's mean heart rate rose to a value of about 100 beats per minute. His first indication of a spacecraft system malfunction occurred at about 23:59 :00 g.e.t. when he noticed that the O.O5g relay light had come on. Heart rate at this time rose sharply to 148 beats per minute and then rapidly declined to the low of


[312] Table 18-XI. Summary of Calibrated Work.

Prework

Work

Postwork

Heart rate, beats/min

Blood pressure, mm Hg

Hear rate, beats/min

Hear rate, beats/min

Blood pressure, mm Hg

Mean

Range

Mean

Range

Mean

Range

Mean

Range

Mean

Range

Systolic

Diastolic

Systolic

Diastolic

Preflight, 5 calibrated work periods

74

60 to 100

104/81

89 to 113

77 to 85

115

91 to 160

85

61 to 120

111/79

89 to 137

71 to 89

Flight, 2 calibrated periods

89

80 to 105

117/77

117

77

131

120 to 145

106

124/95

90 to 130

119 to 129

89

 


[
313] Figure 18-4. MA-9. 12:29:52 Sample of typical biosensor data received at a range station. Blood pressure 117/3 mm Hg. (Recorder speed 25mm/sec.)

 

60 beats per minute and stabilized at a rate of around 100 beats per minute. After a preliminary analysis of the nature of the malfunction indicated by this 0.05g light, the pilot's heart rate varied, with a peak of 142 beats per minute while he was engaged in checking his ASCS system at approximately 30:08:00 g.e.t. Again, the heart rate declined rapidly to its resting level of approximately 100 beats per minute.

 

At about 32:41:00 g.e.t., the pilot was advised to take 5 mg of dextro amphetamine orally which he did shortly after receiving the advice. His heart rate rose gradually beginning at 33 hours elapsed time, with rather marked swings in rate between levels as high as 140 beats per minute and lows of about 80 beats per minute throughout the remainder of the flight. A significant change in heart rate occurred at retrofire when the heart rate rose to 166 beats per minute for no longer than 20 seconds.

 

The heart rate during reentry varied between 120 and 140 beats per minute until drogue parachute deployment when it spiked to 184 beats per minute. It then gradually declined to 164 beats per minute when bioplug disconnect was accomplished subsequent to main parachute deployment.

 

The changes in heart rate throughout this flight seem to fall readily into two categories. Moderate increases in rate with gradual return to the normal resting rate were seen in response to physical exertion. The peak heart rate noted during the flight generally corresponded to levels which have been seen following an equivalent amount of exertion under 1g. A sharper rise of heart rate to high levels in excess of 140 beats per minute was seen as a response when the astronaut was evidently emotionally alerted to a highly significant change in his environmental situation.

 

The ECG intervals were well within normal physiological limits during the major portion of this flight. The A-V nodal beats noted during the prelaunch period were rarely seen during the 34 1/2 hours of flight monitoring. A careful review of all flight records revealed that data from both leads of ECG showed periodic changes in the character of the P wave and the P-R interval, which are consistent with a wandering pacemaker. There were frequent prolonged sinus pauses during the flight which generally are associated with deep inspiration by the pilot, and in the great majority of instances a sinus beat, rather than a ventricular escape, followed the pause. One period in which this rule did not hold was during the sleeping time as the astronaut was passing over the Rose Knot Victor tracking ship. At 17:10:00 and 18:45:00 g.e.t., the medical monitor reported a nodal rhythm which was verified during the postflight examination of the records. Figure

 


[
314] Figure 18-5. MA-19. 16:11:30. Sample of biosensor record at a range station illustrating one of the frequent occurrences of sinus arrhythmia with wandering of the cardiac pacemaker. In this sample, the negative P wave suggests inverse depolarization from the atrioventricular node. Similar changes were observed before flight. (Recorder speed 25mm/sec.).

 

18-5 illustrates this variation. Late in the flight, the sternal ECG lead became rather noisy with a marked fluctuation of the baseline. This fluctuation appeared at times to be synchronous with respiration and at other times to bear little or no relationship to respiratory movements. At this period in the flight, sinus arrhythmia was somewhat more pronounced that it had been early in the flight. A recurrent finding on the record consisted of a simultaneous disruption of the sternal ECG recording with a sharp negative impulse on the relatively insensitive respiratory channel and a sinus pause showing on the side-to-side ECG lead. If is believed that this characteristic pattern resulted from either a habitual deep sighing breath taken by the pilot or perhaps a repeated stretching motion made in an attempt to relieve his cramped position.

 

Blood pressures did not vary remarkably during the flight from preflight values, as shown in table 18-IX.

 

Postflight analysis of the film badges worn by the astronaut revealed a total radiation dose well below a level of medical concern. (See paper 12 for a report on the radiation measurement. )

 

With regard to symptoms related to the flight experience, the pilot repeated the observations of each of his predecessors that the g-forces are readily tolerated and that the sensation of weightlessness is an entirely pleasant experience to which he adapted readily. Astronaut Cooper noticed that his perspective within the spacecraft cabin was altered during the first few minutes of weightless flight. Specifically, he observed that after SECO and during the first 20 minutes or so of weightlessness he felt that the equipment kit located near his right arm was rotated 90°. A similar phenomenon of orientation was reported by the MA-7 pilot. See reference 2. This was not a troublesome illusion to the pilot and gradually vanished as he became accustomed to the altered sensory cues of orbital flight.

 

The astronaut stated that he did not feel particularly hungry during most of the flight and ate primarily because it had been scheduled. However, later in the flight he did feel hungry on one occasion and after eating felt better. Because of problems with the food containers and water nozzle during flight, he was unable to reconstitute properly the freeze- dehydrated food and could only eat one-third of a package of beef pot roast. Therefore, he subsisted on bite-sized cubed food and bite-sized peanut butter ''sandwiches.'' He avoided the bite-sized beef sandwiches, since they had crumbled in [315] their package. His caloric intake during the flight was only 696 calories of the 2,369 calories available to him at launch. He rapidly tired of the cubed "snack-type" foods and this contributed to his low caloric intake. Typical samples of the food types carried aboard from the MA-9 flight are shown in figure 18-6.

 


Figure 18-6. Types of food used during MA-9 flight.

 

The astronaut's water intake was also limited. When the condensate transfer system would no longer permit fluid storage in the 3.86 pound- capacity main condensate bag during the flight he was forced to put condensate water into one of the drinking-water tanks before he had consumed all of its contents. Normal operational procedures required the exclusion of condensate water as a drinking-water source. He began drinking small amounts from his survival-kit water supply, as planned, but he wished to conserve this supply as much as possible. He was not really thirsty until during the last orbital pass, but he was so busy at that point that he did not take time to drink. Because condensate water was placed into the drinking-water tank in which all unknown amount of drinking water remained, it is impossible to make a precise statement as to his water intake during flight, but he did consume more than 1,500 cc.

 

He urinated without difficulty several times during flight and stated that bladder sensations were normal. The urine collection and transfer system worked well, and separate urine samples were obtained at four different times during the flight. It required, however, a considerable amount of time and effort to transfer the urine to the storage bags manually.

 

The astronaut had a very good sleep the night prior to launch and was as rested as possible. He found, even early in the flight, that when he had no tasks to perform and the spacecraft was oriented such that the earth was not in view from the window, he easily dozed off for brief naps. This dozing did not occur during times when there were tasks to perform or items to see through the window. During the period designated for sleep, he slept only in a series of naps lasting no more than 1 hour each. His total sleep time was about 4 1/2 hours. He awoke from these 30- to 60- minute naps feeling alert and rested, but 30 to 45 minutes later he would again doze off. He stated that if there had been another person along to monitor the systems, particularly the environmental control system, he could have slept for much longer periods, but still "no more than 4 to 6 hours in a day." Table 18-XII lists estimated inflight sleep periods.

 

He had a brief period of confusion the first time or two that he awoke in that he did not realize exactly where he was. However, it took him only a very few seconds to become completely awake and oriented. He reported that this brief period of confusion did not occur later in the flight. The pilot stated that he slept "perhaps a little more soundly" than on earth. He did dream, but he did not remember the contents of the dreams. This is consistent with his past experience.

 

He felt that being strapped into the seat made little difference in his sleep, but he definitely had the feeling he was sleeping sitting up. He noted when he awoke that his arms were floating out in front of him, and because of his concern that he might inadvertently trip a critical switch during sleep, he folded his hands and hooked his thumbs under the helmet restraint cables. He was never startled or alarmed to awaken and see his hands floating in front of his faceplate.


[316] Table 18-XII. Inflight Sleep Periods.

Time, g.e.t

Estimated duration, min

Source

02:10:15 to 02:14:00

4

Onboard tape.

05:40:00 to 05:45:00

5

Astronaut record.

13:50:00 to 14:46:00

56

Onboard tape.

14:20:00 to 14:47:00

27

Astronaut record.

15:11:00

(a)

Onboard tape.

15:20:00 to 16:05:00

45

Astronaut record.

16:28:11

(a)

Onboard tape.

16:50:00 to 17:50:00

60

Astronaut record.

08:20:00 to 18:25:00

5

Astronaut record.

18:40:00 to 19:27:00

47

Astronaut record.

19:38:39

(a)

Onboard tape.

21:22:44

(a)

Onboard tape.

27:26:08

(a)

Onboard tape.

Total sleep recorded: 4 hours and 9 minutes

a Short naps, duration not determined.


The oral temperature probe was easily handled by the pilot. It was necessary to use a small hand mirror to check its position on the right ear muff to be sure it was not extending beyond the helmet, but at no time did it interfere with closing the faceplate.

 

The only real discomfort experienced during the flight was associated with the pressure suit being pulled tightly across the pilot's knees. By the sixth or seventh orbital pass, his knees were becoming quite uncomfortable. He alleviated this discomfort somewhat by periodically sliding his feet up past the normal foot position into the tower area of the spacecraft. This action permitted the straightening of his legs to relieve most of the pressure and also allowed him to pull on the legs of the suit to gain a little slack around his knees.

 

The astronaut took 5 mg of dextro-amphetamine sulfate approximately 1 hour 20 minutes prior to retrofire on advice of the MCC surgeon. He stated that within 20 minutes he felt much more alert and confident and seemed to be "more on top of things." He had less tendency to drop off to sleep for the remainder of the flight. There was no apparent degradation in the pilot's performance following this medication. The pilot stated that the drug, as far as he could tell, had the same effects as test doses taken prior to flight.

 

During the last two orbital passes, the carbon-dioxide partial-pressure (PCO2) gage was noted to indicate a rise in the amount of carbon dioxide in the suit. The astronaut actuated the emergency oxygen flow rate for 30 seconds. It did not seem to change the pilot's onboard reading noticeably, although telemetry signals indicated a slight drop. At this time the pilot closed his faceplate and felt that his respirations were deeper and more rapid. This change in respiration could not be confirmed by postflight examination of respiration and heart rate recordings. Although he felt more comfortable with the faceplate open, he kept it closed during the final orbital pass and the reentry as planned. The PCO2 gage indicated about 5 mm Hg at reentry. This concentration is not enough to cause symptoms of hypercapnia on the ground, and there was no apparent interference with the pilot's normal responses.

 

Postflight Observations

 

The spacecraft landed in the water about 4.5 miles from the recovery ship, the USS Kearsarge, and was placed on deck approximately 40 minutes later. In order to gain medical data as early as possible, the NASA flight surgeon [317] aboard the recovery was equipped with an 8-foot extension cord for the biomedical cable. Immediately after the hatch was opened, this cord was attached to the astronaut's biosensor plug and blood pressure fitting and connected to the spacecraft onboard recorder to record blood pressures and ECG before, during, and after egress. This system was extremely effective in deriving egress data.

 

The astronaut was then taken to the ship's sick bay where a comprehensive medical examination and preliminary debriefing was conducted by the NASA flight surgeon in the admiral's inport cabin. The astronaut spent 48 hours on board the ship. Details of his activities during this 48-hour period are shown in table 18-XIII.

 


Table 18-XIII. Pilot Postflight Activities.

Date, 1963

Time, local Midway a

Activity

May 16

12:25 p.m.

Landing.

12:55 p.m.

Spacecraft on deck.

1:09 p.m.

Blood pressure, recumbent in spacecraft.

1:12 p.m.

Egress and blood pressure standing.

1:15 p.m.

Physical examination begun in recovery ship sick bay.

1:45 p.m.

First tilt table procedure.

3:00 p.m.

Examination completed.

3:30 p.m.

First postflight urination.

3:42 p.m.

Second tilt table procedure.

4:10 p.m.

First postflight meal.

5:45 p.m.

First postflight bowel movement.

7:11 p.m.

Third tilt table procedure.

9:30 p.m.

To bed

May 17

7:00 a.m.

Awakened.

7:40 a.m.

Fourth tilt table procedure and brief medical examination.

8:00 a.m.

Breakfast.

9:00 to 11:00 a.m.

Self-debriefing.

2:00 to 5:00 p.m.

Technical debriefing.

7:00 to 9:00 p.m.

Medical debriefing.

May 18

1:00 p.m.

Left recovery ship.

May 20

9:00 a.m. e.s.t.

Comprehensive postflight medical examination at Patrick Air Force Base, Fla.

a To convert times to e.s.t., add 6 hours.


 

The postflight examination began prior to egress from the spacecraft. Approximately 40 minutes before landing, two measurements of the astronaut's blood pressure were recorded while he was still lying in the spacecraft on the deck of the recovery ship. He was then able to egress from the spacecraft without assistance and stand erect on the deck while his blood pressure was again recorded on the onboard tape. Later examination of this 3 1/2 minute record shows that, while he was still in the spacecraft, his blood pressures were 101/65 and 105/87, with a corresponding heart rate of 132 beats per minute. During egress and immediately thereafter while standing upright on the deck, his heart rate rose to 188 beats per minute with atrioventricular dissociation. At that point, another blood pressure recording was attempted and, although the apparatus appeared to cycle normally, no pressure pulses were seen on the recording. His heart then returned to a normal sinus rhythm with a rate of 92 beats for minute at sensor disconnect.

 

After standing on the deck for approximately 1 minute, the pilot began to look pale and, although his face was already wet, new beads of perspiration appeared on his forehead.

 

He swayed slightly and reported symptoms of impending loss of consciousness including lightheadedness, dimming of vision, and tingling of his feet and legs.

 

[318] The cable was immediately disconnected and, with support at each arm, he began to walk away from the spacecraft. After a few steps, 5 to 10 seconds later, he was able to walk without assistance and to salute the ship's commanding officer. There were no other objective changes of this kind throughout the postflight examination and debriefing period.

 

The remainder of the physical examination was conducted in the ship's sick bay and was completed within 2 hours after landing. During desuiting, it was noted that the astronaut was soaking wet, presumable with perspiration. His hands had the white, wrinkled appearance characteristic of prolonged submersion in water. His feet and socks were dry. He complained of being thirsty and his voice was dry and hoarse. He participated actively in the desuiting and examination but appeared tired and less talkative than usual.

 

The urine collection device contained 107 cc of urine. When the soaking wet underwear was removed, the lead u ire to the lower left of the pneumograph sensor on the chest was seen to be disconnected. It is not known whether it separated prior to this time, although it appears probable that it was loose and was making partial contact, held by' the plastic insulation sleeve until the suit was removed. There were some evidences of pressure on the Skill at all lateral sensor locations, but no signs of irritation by sensors, or paste. All sensors were securely in place and the electrode paste seemed to have maintained its normal consistency. At the sensor locations on the left lateral chest, there were narrow semicircular marks that looked like very shallow cuts with a sharp blade. These cuts may have been caused by the thin edge of the tape where the rubber sensor disc slightly overlapped it.

 

There were painful and slightly swollen red areas over each patella caused by the pressure suit having been pulled tightly across the anterior knee when the knee was flexed. Other reddened areas were found over each posterior inferior iliac spine and the posterior spinous process of the fifth lumbar vertebra. There was a diffuse redness over the right lateral iliac area, but none over the left.

 

Additional findings of note were a bilateral conjunctivitis, which probably resulted from drying of the eyes by the constant oxygen flow and a slight reddening around the left tympanic membrane. The astronaut complained that he had a little trouble clearing his left ear during descent. Both ears "crackled" for 6 to 8 hours after recovery as the oxygen in the middle ear was gradually absorbed and replaced with air. This condition is commonly seen in aviators when they have been breathing 100- percent oxygen.

 

Tilt table studies were performed at 1, 3, 6 1/2, and 19 hours after landing. At no time did the astronaut have any subjective complaints, nor were objective changes noted except in heart rate and blood pressure. Specifically, there were no unusual color changes in the feet, as had been noted following the MA-8 flight. The results of the tilt table studies are tabulated and discussed under Special Studies.

 

The medical findings during the initial examination after desuiting are shown in table 18-II and included a blood pressure of 90/80 mm Hg while supine, a heart rate of 86 beats per minute, a respiration rate of 16 breaths per minute, a body weight of 139 1/4 pounds, and a body temperature of 99.4° F taken orally. Three hours after landing his urine showed a specific gravity of 1.031, and the hematocrit was 49. These findings, combined with the clinical evaluation, indicate a moderate dehydration. As has been indicated elsewhere, this dehydration resulted from a reduced intake of food and water during the flight. Detailed results of the blood and urine analyses are contained in tables 18-III to 18-V. The reversal of the ratio of lymphocytes to polymorphonuclear leukocytes during the week following the flight, without a significant change in the total count, has not been explained. This ratio has since returned to normal. A clinical electrocardiograph and a chest X-ray completed the initial postflight examination. The chest x-ray showed no changes when compared with that taken before the flight on May 12, 1963. The ECG showed a moderate rightward shift in the QRS and T axes when compared to that of May 12, 1963.

 

The astronaut slept very soundly for 9 1/2 hours and awoke cheerful and eager to complete the debriefing activities.

 

A brief examination the following day showed that the conjunctival irritation, the hoarseness of his voice, most of the skin pressure marks, [319] and most of the evidence of dehydration had disappeared. The areas of pressure over the knees were still painful and somewhat more swollen shall on the previous day. The sharp semicircular marks were still much in evidence and remained visible for several days.

 

Table 18-XIV shows the pilot's weight loss during several preflight activities and the inflight experience. Intake and output records for the first 24 flours after recovery indicate a fluid intake of 3,900 cc and a urine output of 545 cc.


Table 18-X-IV. Period of Pilot's Weight Changes.

[During the 3-week period prior to flight, the pilot's maximum weight was 149 1/4 lb and his minimum weight was 146 lb. His weight on launch morning was 147 lb and his weight on the recovery ship was 139 1/4 lb.]

Date

Activity

Duration, hr

Weight loss, lb

Preflight

Jan. 5, 1963

Altitude-chamber spacecraft checkout procedure.

9

3.5

Apr. 23, 1963

Flight simulation.

7

2.0

May 8, 1963

Launch simulation.

8 1/2

3.0

May 10, 1963

Flight simulation.

6

2.0

May 14, 1963

Canceled launch.

8

1.3

Flight

May 15/16, 1963

Orbital flight

34 1/3

7.75

 

The pilot returned to the launch site on the fourth day following launch and was examined the following morning. The same medical specialists who examined him prior to flight found him to be in excellent health. The only changes noted were the persistent slight erythema and tenderness of both patellae resulting from the pressure areas in the suit, a continued rightward shift in the QRS and T axes of the ECG, and persistence of the previously noted alteration in blood count. The ECG shift had become less apparent, however. The laboratory studies of blood and urine are contained in tables 18-III to 18-V.

 

The pilot remained in good health and maintained his high morale following this examination. He participated in debriefing sessions and other postflight activities without further medical change.

 

Special Studies

Tilt test evaluation

 

The medical examination performed immediately after the MA-8 recovery suggested an alteration in the pilot's cardiovascular responses to position changes (ref. 1). In order to obtain more quantitative measurements of these responses, all operational tilt procedure was developed for shipboard use. This procedure utilized a Stokes' Litter with cross-bars added for lifting and stabilization. The modifications permitted a tilt of 70° from the horizontal in 3 to 4 seconds. The individual being tested was comfortably secured in the litter' without circulatory interference, by straps across the knees and the upper chest.

 

Heart-rate and blood-pressure measurement were taken at least every minute in all tests and were chosen as the primary indicators of altered functions, in conjunction with observation of visible reactions and subjective comments. Operational use called for minute heart rates calculated from 15-second counts of the right radial pulse with clinical blood pressures taken from the left arm. Greater capability in the [320] Space Medecine Laboratory in Hangar S permitted simultaneous determination of both clinical and BPMS blood pressures and continuous recording of respiration rate and ECG from the biosensor system. Minute heart rates were determined from the directly recorded biosensor data by using 12-second counts made every 30 seconds.

 

Minute respiration rates were determined from 30-second counts made each minute. There were no apparent differences between the clinical and biosensor values.

 

The procedure was carried out in the following manner. After four sets of similar control values, the individual was tilted for 5 minutes and values were sampled at least every minute. Then the subject was returned to the horizontal position for a recording of at least four more sets of similar values. Thus, the minimum time for the complete test was 13 minutes. In order to superimpose a further cardiovascular stress, a modified Flack Test was used in some of the tilts. This test utilizes a tube with a small orifice through which the individual exhales after a maximum inspiration, producing a constant pulmonary overpressure of 40 mm Hg. The Flack Test lasted 15 seconds and was conducted from 3 1/2 to 4 1/2 minutes after the individual was tilted to the 70° position.

 

Preflight results were obtained from 11 tilt tests on the flight astronaut from January 5 to May 10, 1963. Flack Tests were performed with four of the tilts. All of these tilts were performed in conjunction with a spacecraft checkout procedure which required at least 2 hours in the spacecraft couch in the semisupine and the procedure varied from 1 to 5 hours because of uncontrollable operational factors. In each case, the postrun tilts were conducted from 5 to 15 minutes after the procedure, and on January

 


Figure 18-7. Tilt Studies- hear rate responses- MA-9.

 

[321] 5, 1963, a second postrun tilt was performed 1 hour after the first.

 

The hear-rate and blood pressure values are summarized in table 18-XV and illustrated in figures 18-7 and 18-8. The preflight results fall within the ranges reported in the literature. In the prerun period, most heart rates were between 55 and 80 beats per minute. The tilt produced a rise in hear rate varying from 5 to about 20 beats per minute within 30 seconds. This reading gradually increased during the first 2 minutes to rates of 80 and 90 beats per minute, at which point it stabilized. Posttilt values between 100 and 110 beats per minute occurred after 6 1/2 hour run, which was more than twice as long as any of the other runs.

 


Figure 18-8. Tilt studies- blood pressure responses- MA-9.

 

At the beginning of the Flack Test, a bradycardia for 3 or 4 beats usually occurred, followed by an increase in rate to 80 to 90 beats per minute. On several occasions, the maximum observed rates of 110 beats per minute followed a Flack Test. The sudden release of the increased intrathoracic pressure again produced a transient bradycardia followed by an "overshoot" of 10 to 15 beats per minute. Conclusion of the tilt period consistently produced an immediate drop in rate to the pretilt range. Respiration rates were without significant change and are not reported. The increases in diastolic blood pressure were the most remarkable produced by the tilt. The mean increase was 15 mm Hg, but many of the diastolic pressures rose to 20 to 30 mm Hg. An initial systolic drop was followed by a compensatory rise. Postrun tilts produced somewhat more striking blood-pressure changes, with narrowing of some pulse pressures to as little at 6 mm Hg. The maximum systolic levels followed Flack Tests, without an associated diastolic change of significance.


[
322] Table 18-XV. Summary of Tilt Studies.

Subject

Number of determinations

Pretilt

Tilt

Posttilt

Heart rate, beats/min

Blood pressure, mm Hg

Heart rate, beats/min

Blood pressure, mm Hg

Heart rate, beats/min

Blood pressure, mm Hg

Mean

Range

Mean

Range

Mean

Range

Mean

Range

Mean

Range

Mean

Range

Systolic

Diastolic

Systolic

Diastolic

Systolic

Diastolic

Preflight

Cooper preprocedure

5

66

53 to 76

100/73

91 to 112

60 to 87

82

60 to 105

100/86

88 to 144

60 to 94

66

60 to 90

102/75

89 to 114

60 to 88

Cooper postprocedure

6

64

51 to 85

99/74

92 to 128

66 to 82

85

72 to 108

105/87

92 to 134

60 to 97

62

52 to 76

102/75

90 to 114

64 to 94

Cooper and Shepard (all preflight tilts)

15

67

55 to 85

100/71

60 to 82

60 to 82

86

60 to 117

107/86

88 to 145

64 to 98

64

52 to 80

103/72

90 to 114

60 to 94

Postflight

Cooper a

3

83

76 to 81

89/64

86 to 90

52 to 82

123

96 to 144

90/73

80 to 110

68 to 84

76

64 to 88

98/69

90 to 106

58 to 80

Cooper b

1

58

56 to 60

98/61

96 to 100

60 to 62

80

76 to 88

94/68

86 to 100

64 to 78

60

56 to 64

102/56

96 to 108

54 to 58

a Tilts between 1 and 7 hours after landing.
b Tilt 18 hours after landing.

 


 

[323] The ECG demonstrated expected alteration of the QRS axis secondary to position change. Decrease in size of the QRS was especially prominent in the chest lead as a consequence of R-wave depression. There were sinus pauses with an occasional aberrant complex of ventricular origin. The usual pretilt sinus arrhythmia disappeared with the rate increases. The Flack Test produced dropped beats and occasional premature ventricular contractions during the period after sudden release.

 

On no occasion could symptoms of near-syncope be detected. Subjectively, all of these tests were exceedingly well-tolerated. Observation of the physical appearance while tilted showed a tendency to bluish mottling of the hands and feet and a tendency to increased filling of the veins of the legs.

 

Postflight results are shown adjacent to the preflight findings in table 18-XV and figures 18-7 and 18-8. It is readily evident that in the postflight tilt test no. 1 (conducted approximately 1 hour after Ianding) the mean pretilt heart rates were found to be 11 beats per minute higher than during the preflight controls, and the tilt produced a greater heart rate response than any of the preflight tilts. Most of the values from tilt test no. 1 were 120 beats per minute (maximum 132 beats per minute) and exceeded any of the maximum values obtained during the 11 preflight tilts. A Flack Test was not believed to be indicated in view of the tilt response. Tilt test no. 2, conducted 3 hours after landing and 2 hours after no. 1, began from a higher point and showed an even greater rate response; three of the six values were between 140 and 144 beats per minute. Within 4 1/2 minutes after tilt, the heart rate had declined to 132 beats per minute when the Flack Test produced a jump to 145 beats per minute. The tilt was ended and subsequent rates were similar to the pretilt rates. Tilt test no. 3, conducted 6 3/4 hours after landing and 3 1/2 hours after no. 2, showed responses very close to the preflight maximums, which are still excessive, but much less so than the previous two tilts. The rates decrease slightly after the Flack Test. Tilt test no. 4, initiated 19 hours after landing and 12 1/2 hours after no. 3. produced responses very near those obtained before flight with a continued slowing of heart rate after the Flack Test. Unfortunately, simultaneous ECG could not be recorded with any of these tilts.

 

The blood-pressure responses to the postflight tilts were nearly uniform; therefore, only the mean values are shown in figure 18-8. Instead of the preflight systolic drop with prompt compensation and a 15 mm Hg diastolic rise following the tilt, most of the postflight tilts were followed by a systolic drop, a very delayed systolic rise, and little or no change in diastolic levels. Narrowing of pulse pressure to as little as 6 mm Hg was evident in the early postflight tilts. Table 18-XVI presents the postflight blood pressure values during the tilt studies.

 

The blood pressure responses to the final tilt were nearly normal but still showed a delayed compensation for the systolic drop. No visible objective changes occurred and there were no subjective symptoms.

 

In summary, the preflight tilt test produced expected cardiovascular compensatory reactions in that they could be demonstrated by heart rate, blood pressure, and ECG data, and all of these tests were well tolerated. The postflight tilt tests demonstrated the presence of moderate orthostatic hypotension, with far greater heart rates required to maintain effective cardiovascular function. Compensation was achieved. however, and the pilot did not develop even near-syncope. Tilt studies of responses after stresses similar to those experienced during flight are not available. Contributing stress factors including heat stress, the effect of prolonged confinement, dehydration, fatigue, and a possible effect of weightlessness per se are thought to be the principal elements responsible for this change. The picture is further clouded by residual effects of the dextro amphetamine.

 

Calibrated Work

 

A device for calibrated work consisting of a short plastic handle and expandable bungee cords (see fig. 18-9) was fixed within the spacecraft near the astronaut's feet. A limiting cable ensured repeatability of handle travel, requiring 65 pounds of force for each full extension. At 2:25:00 and again at 7:41:00 g.e.t, the astronaut recorded his blood pressure, pulled the device 30 times in as near 30 seconds as possible, and again recorded his blood pressure. The results of these two work periods were

 


[
324] Table 18-XVI.

Tilt

Pretilt

Tilt

Posttilt

Time

Value

Time

Value

Time

Value

May 16, 1963; No.1

13:35:00

90/80

13:46:30

90/70

13:52:00

90/70

13:36:00

90/80

13:46:45

86/70

13:53:00

94/72

13:37:00

90/82

13:47:30

86/78

13:54:00

96/74

13:46:00

88/76

13:48:30

86/70

13:55:00

98/78

13:49:00

84/70

13:56:00

100/80

13:50:00

84/70

May 16, 1963; No.2

15:42:00

86/60

15:44:00

100/70

15:51:00

104/72

15:43:00

88/62

15:44:30

94/74

15:51:30

104/72

15:43:15

88/64

15:45:00

84/78

15:52:00

106/74

15:43:30

88/66

15:46:00

82/72

15:52:30

102/70

15:47:00

92/84

15:53:00

104/72

15:48:00

a 102/80

15:50:00

86/60

May 16, 1963; No.3

19:11:00

88/52

19:15:00

110/68

19:19:45

92/58

19:11:30

88/54

19:15:30

84/70

19:20:15

96/60

19:12:00

90/52

19:16:00

80/68

19:21:00

92/60

19:13:00

90/54

19:17:00

86/68

19:22:00

94/58

19:14:00

88/54

19:18:00

80/74

19:23:00

92/58

19:18:30

a 120/90

19:19:00

80/70

May 17, 1963; No.4

07:42:00

96/60

07:45:30

92/78

07:51:00

96/56

07:43:00

98/60

07:46:00

100/68

07:52:00

100/54

07:44:00

100/62

07:46:30

88/68

07:53:00

100/56

07:45:00

98/60

07:47:00

92/70

07:54:00

108/58

07:48:00

92/66

07:55:00

104/54

07:49:00

86/64

07:50:00

a 110/64

a Values recorded during Flack Tests.



'T' shaped device

Figure 18-9. Exercising device used for calibrated work.

 

compared with five such periods performed at normal gravity in the spacecraft and in the procedures trainer.

 

Subjectively, the astronaut could tell little difference between the work performed under normal gravity and under zero gravity, the effort under zero gravity being, if anything, slightly easier. During flight he felt his postwork breathing was not as labored as it was following control runs, and he thought his heart rate returned to prework values more rapidly. The data, however, do not support this statement.

 

Analysis of the data does not show any striking differences between the one gravity and zero gravity work periods. Inflight mean heart rates during the calibrated work period are 16 beats per minute higher than preflight, but his inflight mean heart rate before work is 15 beats per minute higher. (Return to prework values was slower following the inflight exercise.) The results are given in table 18-XI and presented graphically in figure 18-10. One preflight heart rate during work was 160 beats per minute. This value occurred at the only time in one of the seven periods in which he worked [325] over 0.7 minute and probably reflects the prolongation of the work period rather than indicating a higher work load. During the 18-second recovery period after the test, the preflight mean heart rate dropped to 11 beats per minute over the preflight value, while during the flight it fell to 17 beats per minute over the prework mean.

 


Figure 18-10. Calibrated work- MA-9.

 


Table 18-XVII. Blood chemistries.

Determination

Mar.12, 1963

May 8, 1963

May 12, 1963

May 14, 1963

May 16, 1963; landing + 2 1/2 hours

May 17, 1963; landing + 24 hours

May 20, 1963

Calcium, mEq/l

4.17

4.28

4.60

4.22

4.67

4.56

4.22

Chloride, mEq/l

105

106

100

104

104

102

104

Protein (total), g/100 ml

6.0

6.3

6.0

6.6

6.3

6.2

6.2

Phosphorous, mg/100 ml

4.2

3.5

4.4

4.4

4.5

4.0

3.4

Sodium, mEql/l

153

151

161

144

153

147

146

Potassium, mEq/l

4.6

4.6

5.4

5.2

5.2

5.0

4.9


 

Special Clinical Studies

 

Retinal photography, urine and plasma electrolyte determinations, and plasma enzyme studies comprise special clinical studies. The retinal photographs, taken after the flight for comparison with preflight pictures, show no changes. The results of the urine-electrolyte determinations are presented in table 18-V. The results of the plasma electrolyte determinations appear in table 18-XVII. It should be noted that mineral content of the diet was not provided in equal daily portions during the period of time represented by this table. There was no indication of increased urinary calcium excretion. Sodium and chloride retention shown on May 17 and 18 are consistent with the period of restoration of fluid balance following the dehydration which occurred in flight. All [326] other values are within the normal range for Astronaut Cooper. Enzyme studies have been made in each of the Mercury flights as part of a development program. The clinical significance of the data is still undergoing validation; therefore, interpretation has not been attempted. Consequently, results are not reported in this paper.

 

Conclusions

 

On the basis of the total experience obtained during Project Mercury, the following medically significant facts have been derived from the medical operations.

(1) There has been no evidence of significant degradation of pilot function attributable to space flight. A mission of 34 hours in the zerogravity condition has been well tolerated and all measured physiologic functions remained within anticipated ranges throughout this flight.

(2) Sleep in flight is possible and subjectively normal.

(3) The radiation dose received by the astronauts to date is considered medically insignificant.

(4) There is no evidence of abnormal sensory, psychiatric, or psychological response to an orbital space flight of up to 1 1/2 days.

(5) Following missions of 9 and 34 hours duration, an orthostatic rise in heart rate and fall in blood pressure has been noted and has persisted for between 7 and 19 hours after landing. The changes were of greater magnitude following the 34-hour flight than those following the 9- hour flight; however, all changes disappeared in a similar time interval in both cases. The implications of this hemodynamic response will have to be given very serious consideration as longer missions are undertaken. No other clearly significant changes have been found in comprehensive preflight and postflight physical examinations.

 

Acknowledgments. The following individuals helped in preparation of and data processing for this paper and their assistance is gratefully acknowledged: the Space Medicine Branch, Crew Systems Division, NASA Manned Spacecraft Center, particularly Miss Rita Rapp and also the bioinstrumentation section; Edward C. Knoblock, Ph. D., Walter Reed Army Institute of Research, Washington, D.C); Ashton Graybiel, M.D., U.S.N. School of Aviation Medicine, Pensacola, Fla.; Donald Flinn, M.D., and W. Bruce Clark, M.D., U.S.A.F School of Aerospace Medicine, Brooks Air Force Base, Texas; David H. Newbern, M.D., Orlando Air Force Base, Fla.; Charles W. Upp, M.D., Selfridge Air Force Base, Michigan; Robert D. Bolinder, M.D., Fort Dix, New Jersey; Walter Frajola, Ph.D., Ohio State University; and the many medical flight controllers.

 

References

 

1. Staff of NASA Manned Spacecraft Center: Results of the Third United States Manned Orbital Space Flight, October 3, 1962. SP-12, Supt. Doc., U .S. Government Printing Office (Washington, D.C.).

2. Staff of NASA Manned Spacecraft Center: Results of the Second United States Manned Orbital Space Flight, May 24, 1962. SP-6 Supt. Doc., U.S. Government Printing Office (Washington, D.C.).

3. Staff of NASA Manned Spacecraft Center: Results of the First United States Manned Orbital Space Flight, February 20, 1962, Supt. Doc., U.S. Government Printing Office (Washington, D.C.).

 


1 Currently a research fellow In the Department of Physiology at the University of Washington, Seattle, Washington.


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