Minimum Environmental Control & Life Support Guidelines for Manned

Commercial Suborbital Reusable Launch Vehicles

Arnold A. Angelici Jr., M.D.May 19, 2004

NRC Grant Proposal

• Develop draft guidelines for minimum requirements for environmental control and life support systems (ECLSS) on manned commercial reusable launch vehicles

R&D Project

• The Civil Aerospace Medical Institute (CAMI), which is the medical certification, research, and education wing of FAA’s Office of Aerospace Medicine is tasked under an R&D project to support FAA/AST:– NRC of National Academy of Sciences approved

CAMI to establish a post-doctoral research associateship program in support of FAA research activities

Approach to the Completion of the Guidelines

• A list of 19 aeromedical & environmental safety issues was developed. They were combined into modules based on similar or overlapping criteria. Some of these modules include:- Cabin atmosphere and air quality*

- Temperature and humidity- Short and long duration G*

- Restraint systems - Vibration and noise - Fire detection and suppression - Radiation *Note: Presentation focuses on these.

Various sources• NASA

– Manned space flight experience

• FAA/CAMI– Research experience

• Current literature– Non-classified military research involving

humans in aerospace environments

• OSHA (Part 1910), NIOSH databases– Rule making based on research to make the

workplace safer

Cabin AltitudeSpacecraft designers will select a capsule design

altitude:

Sea Level to 10,000 feet

10,000 to 27,000 feet

27,000 to 40,000 feet

and will have to deal with

depressurizations

Cabin Pressurization vs. % Oxygen

Cabin Altitude Option:

If it is from Sea level to 10,000 feet– May have partial pressure of oxygen at the

altitude equivalent or– Enrich the cabin atmosphere so that the alveolar pAO2 is between Sea Level and 10,000 feet by enriching the cabin oxygen concentration from 21% to a maximum of 24%

Cabin Altitude Option:

If it is between 10,000 feet and 27,000 feet then:– Oxygen should be provided to the crew by a

diluter demand system for the entire time that the cabin altitude is at these levels at an oxygen concentration that will maintain alveolar pAO2 between Sea Level and 10,000 feet

Cabin Altitude Option:

If it is between 27,000 feet and 40,000 feet then:– Oxygen should be provided to the crew by a

pressure demand system for the entire time that the cabin this altitude and provide an oxygen concentration that will maintain alveolar pAO2 between Sea Level and 10,000 feet

Critical Cabin Altitude:

If it is 40,000 feet for any amount of time, then:– Oxygen should be provided to the crew by a

means that would result in an oxygen concentration that will maintain alveolar pAO2 between Sea Level and 10,000 feet

– And protect them from the effects of very low barometric pressures

Cabin Atmosphere

• Carbon dioxide (CO2) should not exceed

0.05 psi (0.4 kPa) or 0.5% sea level equivalent pressure

• There should be a means of monitoring the concentration of CO2 in the cabin throughout the mission/flight

Carbon MonoxideTable 1 — Effects of various CO

concentrations at sea level.(At altitude, the effects of CO

poisoning and altitude hypoxiaare cumulative.)

CO Concentra

tion(parts per million)

Symptoms

35 No obvious symptoms after 8 hours of exposure.

200 Mild headache after 2 to 3 hours.

400 Headache and nausea after 1 to 2 hours.

800 Headache, nausea and dizziness after 45 minutes; collapse after 2 hours.

1000 Unconsciousness after 1 hour.

1600 Unconsciousness after 30 minutes.

Table 2 — Effects of various COHb saturations.

COHbSaturation (%)

Symptoms

0 - 10 None. (Smoking yields 3% to 10% COHb.)

10 - 20 Tension in forehead, dilation of blood vessels.

20 - 30 Headache and pulsating temples.

30 - 40 Severe headache, weariness, dizziness, vision problems, nausea, vomiting, prostration.

40 - 50 Same as above, plus increased breathing and pulse rates, asphyxiation.

50 - 60 Same as above, plus coma, convulsions, Cheyne-Stokes respiration.

60 - 70 Coma, convulsions, weak respiration and pulse. Death is possible.

70 - 80 Slowing and stopping of breathing. Death within hours.

80 - 90 Death in less than 1 hour.

90 - 100 Death within minutes.

Acceleration Loads

• Long Duration G loads (sustained)

• Short Duration G loads (sudden)

Acceleration LoadsLong Duration: > 0.1 sec.

• (gradual onset < 0.1G/sec.):

+4 Gz

-2 Gz

4 Gx

1 Gy By J. Burns & Wm. Albery, AFRL/HE

G-LOC

• Hazards to the safety of manned commercial space flight due to G-LOC– Pilot might be unaware that G-LOC had

occurred– Lack of physical control post G-LOC– Poor insight to what had happened– Embarrassment over loss of consciousness– Return to consciousness but not to control

Incapacitation due to G-LOC

• Absolute incapacitation +Gz: 16.6 ± 5.9 sec.• Relative incapacitation +Gz: 14.4 sec.• Total incapacitation +Gz: 31.0 ±11.7 sec.• G-LOC occurred between 3.1 and 4.0 G

– The period of Relative incapacitation is accompanied by confusion and disorientation.

– Training reduced the duration of Relative incapacitation by 8.5 sec.

Mitigation• Training of air crews by exposure to G-

loads has demonstrated:• Improved tolerance to G-loading

• Reduction in the duration of relative incapacitation time

• Monitoring• Incorporate an “Auto-recovery” mode into the

vehicle if the flight profile would place the crew at risk of G-LOC

• Use of an anti-G suit

Short Duration Acceleration Loads (<0.1sec.)

• Aircraft ejection seat firings - up to 17 +Gz• Crash landings - from 10 to greater than 100 G's

(omni directional)• Orbiter crew compartment design loads for crash

landings are 20 Gx and 10 +Gz• Violent maneuvers - approx. 2-6 G's (omni

directional)• Parachute opening shock - approx. 10 +Gz

• Reference:5.3.2.1.3, p.5-31; NASA-STD-3000 Rev. B

Duration of Force <0.1 Sec. Reference: Fig. 5.3.3.3-1, p. 5-40, NASA-STD-3000

Direction of impact acceleration

Impact limit

Rate of impact

±Gx 20 G 1,000 G/sec.

±Gy 20 G 1,000 G/sec.

±Gz 15 G 500 G/sec.

45° off-axis (any axis)

20 G 1,000 G/sec.

Restraint Systems• Utilize the knowledge

from CAMI’s Biodynamics research to develop appropriate guidelines for restraint systems for Manned CRLV’s

• Proper use of the restraint system will prevent serious injury in normal operation and have reasonable expectations of survival in the event of a crash

Restraint Systems• The restraint systems must protect the crew

and passengers from:– Sudden, short duration G-loads (Transient

Acceleration)– Sustained duration G-loads

(Sustained Acceleration)• Acceleration (launch)

• Deceleration (re-entry)

– “Zero G”

Schedule

• Complete R&D project in August 2004