**3.7 Crash Survival and Crashworthiness Issues:**

Aborted launch/take off considerations

Emergency landing considerations

![](media/image1.jpeg){width="5.996527777777778in"
height="3.9479166666666665in"}

A European Space Agency astronaut is assisted out of the Soyuz landing
craft. Note the anomalous landing which left the Soyuz on its side (the
bottom of the craft is visible at the right of the picture), rather than
upright as is nominal. Though anomalous, this landing was
[not]{.underline} a "crash".

**CRASH SURVIVAL AND CRASHWORTHINESS ISSUES**

This chapter is designed to provide you with a basic understanding of
the possibilities for mishaps during spaceflight. The equipment provided
for improving survival is described, and various aborted launch and
emergency landing scenarios are described.

![](media/image2.jpeg){width="5.694444444444445in"
height="5.694444444444445in"}

**Crash Survival and Crashworthiness Issues**

Crash survival for space flight depends greatly on the phase of flight
(launch, in-flight, landing). To date, the U.S. program has suffered the
loss of two orbiters, one on launch (Challenger, January 1986), and one
on landing (Columbia, February, 2003). In neither case was the crash
survivable, but both caused reexamination of the crew escape systems and
crashworthiness of the Shuttle fleet. The Soviet/Russian program also
suffered several losses and near-tragedies and adapted their vehicles
appropriately.

![](media/image3.jpeg){width="2.875in" height="2.875in"}

Figure 1: The Shuttle Challenger was lost shortly after launch when a
faulty O-ring seal allowed flames to burn through into the external fuel
tank. (http://datamanos2.com/challenger/multimedia.html)

![](media/image4.jpeg){width="4.623611111111111in"
height="2.4805555555555556in"}

Figure 2: The Shuttle Columbia breaking up during reentry due to a
breach in the structure caused by a foam strike.
(http://www.jsonline.com/news/nat/columbia/)

In both of the Shuttle disasters, the crew compartment survived the
initial event, but the astronauts died from blunt force trauma. In the
case of the Challenger, the crew were killed when the crew compartment
impacted the ocean; in the Columbia, deaths occurred when the crew
compartment finally tore apart as the Shuttle disintegrated around it
and the astronauts were flung out into the atmosphere's air stream. The
crew compartment is deliberately constructed to be the most robust part
of the orbiter, but in both the Challenger and Columbia disasters, the
additional protection was of no value. There was no way for the crew to
effect an escape despite the fact that the cabin was not immediately
compromised. Unlike many terrestrial aircraft, there are no ejection
seats in the current Shuttle -- weight and volume constraints precluded
their inclusion once the crew size increased beyond two. Instead, other
escape systems are used by space travelers, some of which have been
modified as a result of lessons learned in the two disasters.

**Design Parameters**

To maximize the crashworthiness and crew survival aspects of future Crew
Expedition Vehicles (CEV), NASA is applying the lessons learned from the
space program as well as military and civilian aircraft and other
vehicle programs. Specifically, NASA has established general vehicle
design requirements and formalized them in documents such as
NASA-STD-3000 MSIS Rev B and JSC 28354 Human-Rating Requirements.

All future vehicles will be required to meet these baseline requirements
for human crew operations. Specified parameters include vehicle and
system performance, environmental control specifications, human factors
guidelines, medical limitations, crash survival and crashworthiness, and
support requirements. The requirements are not intended to be design
solutions, but merely to guide the vehicle architects as they develop
concepts and designs.

**Landing Impact Forces**

Impact deceleration limits are required to minimize injuries associated
with landing. Specifically, risk of serious or incapacitating injury in
a deconditioned and ill or injured crewmember can be no greater than
0.5% (as defined by the Brinkley Dynamic Response Model). This figure
represents an acceptable level of risk to the crewmember, while still
allowing vehicle designers a degree of latitude in developing a method
of landing. The limits established in the 1990's were 10 G in the
+/-G~x~ for 0.2 seconds, 5 G in the +/- G~y~ for 0.2 seconds and 5 G in
the +/- G~z~ for 0.2 seconds.

**Extraction**

Following a landing after a long duration mission, the entire returning
crew may be partially or completely incapacitated due to
neurovestibular, cardiovascular, and musculoskeletal deconditioning.
This complicates crew survival and creates additional concerns for the
vehicle architects. To address this, the vehicle design is required to
permit the extraction of crewmembers by Search and Rescue (SAR) forces.

**Post-landing Recovery**

Crew recovery after landing is not considered complete until the space
travelers have reached definitive medical care. For a nominal Soyuz
landing from the ISS, local SAR forces, augmented by NASA personnel
including the crew surgeon, locate the capsule and extract the
crewmembers. The Soyuz Descent Module is equipped with radio and light
beacons to assist in its locating, while the crew have recently been
given GPS and satellite phones. The vehicle itself is equipped with
survival equipment and provisions in case SAR forces cannot reach the
crewmembers for an extended period of time, an event which has happened
occasionally over the course of the Russian space program.

However, in the event of a medical evacuation from orbit, where
returning crew will be ill or injured, it may be critical for the
patient(s) to reach a Definitive Medical Care Facility (DMCF) within a
pre-determined period of time from station evacuation. As a result,
requirements and procedures continue to be developed to minimize this
time, and these have consequences for design requirements. Affected
parameters include: the time required to land a vehicle, where the
vehicle can land, the recovery vehicle and the Post Landing Recovery
Forces (PLRF) that must be available. For example, a vehicle which can
depart the Space Station and land at multiple locations within 3 hours
would require a more agile and responsive PLRF (i.e. one that can
respond more quickly and to more locations) than the force required for
a Soyuz landing which has more limitations on its re-entry.

Recovery of a crew in an emergency return is different from the
well-choreographed and planned nominal landings of both the Soyuz and
Shuttle. NASA has specific plans in place for crew recovery at different
locations where a crew may land, whether the return vehicle used is a
Shuttle or Soyuz, and whether the crew are returning from a short or
long duration mission. The required capabilities of recovery forces are
specified in NASA documentation and include rescue personnel, crewmember
extraction capabilities, helicopter or aircraft evacuation capability
and/or ground medical transport. SAR forces at all potential landing
sites are required to be familiar with the space vehicles used for
evacuation.

**Crew safety equipment**

During launch and landing, the crew wear several pieces of equipment
designed to improve their ability to survive a crash. Most of these are
similar (though specific items vary) in both the American and Russian
programs. These include a special pressure suit, parachute, rescue
equipment, and survival equipment. In addition, the orbiter itself is
equipped with several devices to improve crew survival, including a side
hatch jettisoning system, egress slide, escape window, escape pole for
mid-air bailouts, and "sky genie" rappelling devices.

**Crew Suit**

The suit worn by astronauts in the U.S. program has changed over the
years. Early in the program, no pressure suit was used, merely a (baby
blue) jumpsuit.

![](media/image5.jpeg){width="1.7645833333333334in"
height="2.3020833333333335in"}
![](media/image6.jpeg){width="3.2111111111111112in"
height="2.3118055555555554in"}

Figure 3: At left, the Challenger crew leave for the launch pad at
Kennedy Space Center. At right, the crew pose for their formal portrait
in the blue jumpsuits and helmets that were the standard uniform during
launch and landing. (http://datamanos2.com/challenger/multimedia.html)

After the loss of the Challenger, STS mission 51-L on 28 January 1986,
the decision was made to have the crew wear pressure suits during launch
and re-entry in order to protect them in the event of a loss of cabin
pressure at altitudes up to 30 km and to insulate them from the cold air
and water in the event of a bailout. A suit was thus developed to
provide combined anti-G protection, emergency pressurization,
anti-exposure protection, high altitude escape, and sea survival for
shuttle orbiter crews. These partial pressure (twin-walled bladder type)
suits were used with a specially integrated parachute, emergency oxygen
system and survival kit pack, which were worn on the back in combination
with the suit. Each LES garment weighed, with helmet, approximately 11
kg (excluding parachute/survival pack). The initial partial pressure
Launch and Entry suit (LES) was a modified CSU-4/P suit with
non-conformal full pressure helmet, dual neck dam, integrated exposure
suit, an anti-G protection system, parachute harness and flotation
equipment. This suit was eventually replaced by the (orange) full
pressure Advanced Crew Escape Suit (or ACES). The major difference
between the LES and ACES is the latter's full pressure nature and
integrated liquid cooling garment.

![](media/image7.jpeg){width="1.7034722222222223in"
height="3.7284722222222224in"} ![](media/image8.jpeg){width="2.43125in"
height="3.709722222222222in"}

Figure 4: At left, a picture of the partial pressure LES used from 1986
until 1995. At right, the STS-107 Columbia crew walk out of the O&C
Building en route to the launch pad, clad in their ACES "pumpkin suits".
(http://www.astronautix.com/craft/shuleles.htm and
http://www.ptak.org/splats/03.01.space_shuttle_launch/nasa_shuttle_crew_9230.jpg)

The current bright orange suit, affectionately dubbed the "pumpkin
suit", is donned with the help of a cadre of suit technicians in the
Suit Room of the Operations and Checkout (O&C) Building at Kennedy Space
Center before the crew head to the launch pad. Following successful
insertion into orbit, the crew doff these suits and stow them until just
before they take their seats for reentry. As might be expected, donning
and removing these suits in the small, microgravity environment of the
Shuttle middeck is a tricky task, and crew members must take turns and
assist each other. Gloves and helmets are usually the final items to be
donned, as crew members often find them hot and/or uncomfortable.

If the helmet or gloves are not worn, however, the protection offered by
the suit is radically compromised. The suit functions as a "hard"
pressure suit at cabin altitudes above 60,000 feet, when bailout is not
yet possible, then it can serve as an unpressurized suit at altitudes
below 40,000 feet, where a bailout could occur. If properly worn, the
suit can protect the crew from a loss of cabin pressure or cabin oxygen
to a 100,000 foot altitude, protect against the pooling of blood in the
lower extremities, and protect against the cold temperatures of the
upper atmosphere or ocean water in the event of a bailout. The suit
delivers oxygen at suitable pressure and quantity (under 100,000 feet
altitude) and protects the wearer from a toxic environment, including
smoke, combustion products, and flames.

The ACES is a full pressure suit that provides protection at altitudes
up to 100,000 feet to the crew for an indefinite period of time after
loss of cabin pressure. It is a 100% oxygen environment at 3.5 psi.
Mobility is not constrained by the loose fit, and there are six pressure
seals (helmet visor, neck dam, main suit zipper, bio-instrumentation
pass-through (BIP) plug, and both gloves). The outer garment is made of
orange flame-retardant Nomex, which covers a single pressure bladder.
The bladder covers the body, with the exception of the head and hands,
and is laminated with Gore-Tex. A detachable anti-g suit can be worn
underneath during reentry.

![](media/image9.jpeg){width="4.875in" height="3.6569444444444446in"}

Figure 5: LES Suit Schematic: 1) Mission Specialist seat; 2) crewman; 3)
helmet; 4) anti-exposure / counter pressure garment; 5) boots; 6)
parachute harness; 7) parachute pack; 8) life raft with sea dye marker;
9) suit mounted oxygen (O2) manifold; 10) anti-gravity (anti-g) suit
controller; 11) emergency O2 supply; 12) seawars; 13) ventilation fan;
14) orbiter O2 line; 15) headset interface unit (HIU); 16) communication
(COMM) line to HIU; 17) flotation device. (http://nix.nasa.gov/)

The suit controller is located on the right chest and regulates internal
suit pressure through a valve which maintains pressure in the suit
bladder and thus on the body. The valve opens to allow exhaled air to
flow through the bladder and controller, but closes if the ambient cabin
pressure is equivalent to that above an altitude of 35-40,000 feet. When
the valve is closed, the crewmember's respirations inflate the bladder
until the internal suit pressure and cabin pressure is 3.5 psi. The suit
oxygen regulator is the means by which pressurized oxygen enters the
helmet from stores in the orbiter. Two exhalation valves between the
helmet cavity and suit bladder allow exhaled breaths to enter the
bladder and exit through the suit controller. A relief valve on the
right hip will open if the suit pressure reaches 5.5 psi and remains
open until the pressure has fallen to 3.5 psi.

![](media/image10.jpeg){width="3.2729166666666667in"
height="4.082638888888889in"}

Figure 6: Astronaut Eileen Collins in her ACES. The suit controller is
visible on her right side. (http://nix.nasa.gov/)

The detachable anti-g suit which is worn (only) during landing has both
abdominal and partial leg bladders and is controlled by a device at the
upper left leg. The suit's function is to apply pressure to the body to
counteract g-forces and prevent the compromising of cerebral perfusion
from pooling of blood in the lower extremities. Although the orbiter
does not perform any high-g maneuvers as terrestrial fighter aircraft
do, the crew's microgravity-adapted physiology puts them at very high
risk for orthostatic hypotension, and the suit has proven helpful in
preventing presyncope during landing.

**Helmet**

The suit's helmet has as its main purpose the protection of the head
during bailout. In addition, it also provides a conduit between the CCA
(Communications Carrier Assembly) and HIU (Headset Interface Unit). It
has a rotating faceplate with pressure visor and rotating sunshield. An
anti-suffocation valve allows ambient air to enter if the visor is
closed and no oxygen is available. (Caution: It can also let in water if
the crew member is submerged.) The valve is designed to open when the
pressure inside the helmet is 0.54 psi less than outside pressure.

![](media/image11.jpeg){width="5.123611111111111in"
height="3.842361111111111in"}

Figure 7: Donning the CCA for a training exercise. Note this crewmember
is wearing the earlier (training) version of the LES, which was a dark
blue in color. (http://nix.nasa.gov/)

The CCA is also known as the "comm cap"; it contains all equipment
needed for voice communication. There are two microphones with auto-mute
capability during oxygen flow into the helmet and two independent padded
earmuff-type earphones. The connector is located at the back of the cap.
The HIU provides volume control and push-to-talk (PTT) capabilities for
space to ground and intercom communication. It amplifies the microphone
signal from the CCA and connects to the helmet via a cable from the back
of the helmet to the communication pigtail and then to the HIU.

**Gloves and Boots**

The gloves are made of Nomex and silicone, with adjustable straps to
reduce their rigidity when pressurized. They mate to the suit sleeves at
a ring and have a colored patch to identify the wearer[^1]. The gloves
have a quick disconnect capacity, but must be kept on in order to keep
water out during a water landing, and they pressurize when the suit
pressurizes. The boots are made of leather, Nomex, and rubber, with a
zipper for quick donning and laces for fit adjustment. Like the gloves,
the boots have colored patches for crew identification.

![](media/image12.jpeg){width="3.8756944444444446in"
height="2.9069444444444446in"}

Figure 8: Donning boots, with a little help from the suit technicians,
before a training exercise. (http://nix.nasa.gov/)

**Cooling System**

To prevent heat stress, the suits have a cooling system. The newer
system is called TELCU (Thermal Electric Cooling Unit). Crew members
wear a liquid cooling garment (LCG) which has a network of vinyl tubes
running through the long underwear-like two piece suit and connecting at
the bio-instrumentation pass-through (BIP) plug. Water flows through the
tubes to cool the crewmember. Water enters the TELCU unit from the LCG
and travels through a channel where heat exchange occurs, aided by two
fans. The cooled water is then pumped back to the LCG via the BIP, where
it helps to improve the crewmember's comfort. The crewmember can control
the TELCU either by a control switch on top of the TELCU (settings are
"off", "low" which sends 70^o^F water to the LCG, or "high" which sends
80^o^F water to the LCG) or through a clamp on the LCG inlet line, which
controls water flow and thus cooling.

**Personal Parachute Assembly**

In addition to the pumpkin suit, the crewmember also wears a parachute,
consisting of a parachute harness and personal parachute assembly (PPA).
The harness is the link between the astronaut and parachute, and it
supports the crewmember's weight through nylon shoulder, chest, and leg
straps. In addition, it holds several pieces of survival and rescue
gear, such as an emergency oxygen supply, life preserver unit (LPU),
carabiner with Velcro cover, and a supply of emergency drinking water.
The harness attaches to the PPA at four points. The PPA contains the
parachute and risers, a SARSAT (search and rescue satellite-aided
tracking) radio beacon), and a single person life raft. During nominal
operations, it serves as a seat back cushion.

![](media/image13.jpeg){width="2.6638888888888888in"
height="4.061805555555556in"}

Figure 9: Having fun during survival training. This drill simulates a
parachute drop into water. This picture not only shows the parachute
harness, but also the leg pockets where additional survival gear is
stowed. (http://nix.nasa.gov/)

The PPA also has a D-ring for attachment to the Shuttle's bail out pole,
the parachute deployment system, and a ripcord to serve as a backup
system for chute deployment. There is also a drogue chute release knob,
a backup method to deploy the main chute once the drogue has deployed.
The pilot chute has an 18 inch diameter canopy and serves to pull out
the 4.5 foot diameter drogue chute. Once the drogue chute has stabilized
the crewmember, it is safe for the 26 foot diameter main chute to open.
This is a modified circular military canopy with four anti-oscillation
windows and a pyrotechnic reefing system to minimize the opening shock
to the astronaut. The seawater-activated release system (SEAWARS) is
attached to each parachute riser. When it is immersed in seawater, the
SEAWARS releases the riser, separating the crewmember from the chute.
There is also a manual backup system.

Survival gear is stowed in several places. In the left suit leg pocket
there is a flare kit, containing seven cartridges, each of 4.5 seconds
duration and visible for up to 50 miles. There are also a knife,
exposure mittens, two 12 hour chem-lights, and one strobe light good for
6-9 hours of continual use or 18 hours when used intermittently. Lastly,
there are smoke/flare signals which produce 16 seconds of orange smoke
or 20 seconds of red light. A survival radio is located in the right
suit leg pocket. It can both transmit and receive. At 90% receive/10%
transmission, its battery will last 24 hours. It can send out a beacon
continuously and comes with an earphone and spare antenna. Also in the
pocket are motion sickness tablets (scopolamine/dexadrine) and a signal
mirror.

The horseshoe-shaped life preserver (LPU) is attached to the harness. It
can keep an unconscious person's head out of the water and will inflate
automatically from carbon dioxide bottles upon immersion in water. It
can also be manually inflated if necessary.

![](media/image14.jpeg){width="4.625694444444444in" height="4.5in"}

Figure 10: Staying afloat during water rescue training.
(http://nix.nasa.gov/)

An emergency oxygen system containing two bottles provides an additional
10 minutes of oxygen at moderate levels of exertion. The harness also
holds a two liter supply of drinking water, a two foot tether line, and
a carabiner which can be used by search and rescue forces to hoist the
crewmember into a rescue vehicle.

Lastly, the PPA contains a single person life raft. It is composed of
eight rows of inflatable tubes, of which three inflate immediately upon
immersion via the automatic firing of a carbon dioxide canister. The
crewmember is then expected to fire a second CO2 cartridge to inflate
the remaining five rows, although the raft can be inflated by mouth if
necessary.

![](media/image15.jpeg){width="5.0in" height="3.20625in"}

Figure 11: Bailing out the life raft during training.
(http://nix.nasa.gov/)

The raft has two spray shields with Velcro closures, a bailing cup and
pump, and reflective tape on all sides. It is connected to the PPA by a
12 foot Kevlar tether. The SARSAT radio is in a pocket on the spray
shield; its antenna loops around the shield, and it is automatically
activated upon deployment of the parachute. The radio transmits on
several frequencies: 121.5 (international distress), 243.0 (military
distress), and 406.0 (satellite search and rescue). There is also a sea
anchor with a dye marker tethered to the exterior of the raft, along
with an extra dye packet.

**Orbiter equipment**

**Hatch**

The orbiter has a side hatch which is normally used for egress after
landing. It also comes equipped with an escape slide, similar to those
seen on commercial aircraft, for rapid exit in an emergency. If the side
hatch is unavailable, window 8, located on the roof of the crew cabin
when the orbiter rests on its landing gear, can serve as an emergency
escape hatch. If the crew exit via the window, they then use "Sky Genie"
descent control devices to rappel off the sides of the orbiter and reach
the ground safely. For an in-flight bailout, the most hazardous escape
condition, the orbiter has an escape pole to prevent the crew from
tumbling against the wing and rear of the orbiter after they jump from
the crew compartment via the side hatch.

The side hatch is the primary means of entering and exiting the Shuttle.
It weighs 300 lbs (136 kg) and has a 40 inch diameter, including a 10
inch diameter window[^2]. It has a pressure seal which is compressed by
the latch mechanism in the locked position. The hatch opens outwards 90
degrees; its rate of opening is controlled by a hydraulic attenuator.
Normally, the ground team seals and opens the hatch, but the crew can do
so by means of a pyrotechnic system which both depressurizes and
jettisons the hatch. As soon as the orbiter reaches orbit, this system
is deactivated by MS3, who inserts a safing pin into the control panel
on the middeck floor. This prevents accidental hatch opening while in
orbit.

![](media/image16.jpeg){width="5.291666666666667in" height="3.96875in"}

Figure 12: The size of the side hatch (this one on a full size shuttle
mock up) is shown in this picture of astronaut Kathryn Thornton.
(http://nix.nasa.gov/)

Following landing, if the ground support personnel are present, they
open the hatch using an external opening device. The cabin atmosphere
must be vented first, however. This usually takes 30-120 seconds.

In the event of an emergency landing where the hatch needs to be opened
by the crew, for example in the case of a mid-air bailout, the crew
would first pull a vent valve T-handle located behind the waste
management compartment. This opens a 15 square inch hole between the
crew compartment and payload bay, depressurizing the cabin in a
controlled manner. Once the cabin and ambient pressure have
equilibrated, the hatch jettison T-handle is pulled. This blows the
hatch by activating four linear-shaped pyrotechnic charges, two per
hinge, which sever the hatch hinges. Simultaneously, two expanding tube
charges sever the 70 bolts which hold the hatch adapter ring to the
Shuttle, and 3 thruster packs push the hatch away at a speed of about 45
feet per second.

The escape slide, also known as the EESS (Emergency Egress Slide
System), can be used whether the hatch is opened in a normal fashion or
jettisoned. It is activated by the crew, inflated automatically via an
argon bottle, and remains usable for at least 6 minutes.

![](media/image17.jpeg){width="4.875in" height="3.6569444444444446in"}

Figure 13: The EESS in use during a training drill.
(http://nix.nasa.gov/)

**Window Escape System**

The window escape system is intended for use when the side hatch is
unavailable. First the crew must jettison the escape panel via a
pyrotechnic system, then attach to a "Sky Genie", climb onto the MS2
seat and out window 8, and then rappel down the Shuttle's starboard
side. The pyrotechnics are mechanical and require no power to activate.
The handle is located on the top of flight deck panel C2, although a
second, external control panel is located on the starboard side of the
orbiter so that rescue personnel can also open window 8, if necessary.
When triggered, the system ejects the window's outer thermal pane and
frame outwards and upwards. 0.3 seconds later, the window's two inner
panes hinge down and aft, coming to rest on the aft flight deck panel. A
capture device prevents the inner panes from opening too forcefully and
holds the panel open. If the system fails, a prybar is available to the
crew as a backup.

The "Sky Genie" system is used to lower crewmembers from the top of the
orbiter to the ground quickly but safely. It consists of a descent
device, 50 feet of nylon rope, a rope bag, crewmember tether and hand
loop, swivel snap shackle, and emergency release tab. It can be used
from either window 8 or the side hatch if the EESS is unavailable.

![](media/image18.jpeg){width="2.5319444444444446in"
height="3.8756944444444446in"}

Figure 14: Astronaut Pamela Melroy practicing with the Sky Genie.
(http://nix.nasa.gov/)

In the event that neither the side hatch nor window 8 are available,
rescue personnel will have to gain access by cutting into the crew
compartment at a specially designed section of the hull. This will take
at least 45 minutes and is obviously a method of last resort.

**Bailout Escape Pole**

The bailout escape pole is designed to guide crewmembers to a trajectory
which will clear the Shuttle's left wing. It is a 275 pound curved steel
and aluminum pole with a spring activated, telescoping deployment and
eight lanyards available for the crew[^3]. The aluminum housing attaches
to the middeck ceiling and side wall by the side hatch. When the Shuttle
reaches orbit successfully, the pole is removed and stowed.

In the event of a midair bailout, the crewmember will uncover the D-ring
on his PPA right riser, lean forward into the hatch area, attach the
D-ring to the snap hook on the outermost lanyard, and fall forward, out
the open hatch. The pole will carry the crewmember a safe distance away
from the orbiter.

**Nominal crew operations**

Under normal conditions, the crew will don their ACES suits in the O&C
building, then go to the launch pad. There, at the 195 foot level of the
Fixed Service Structure (FSS), the platform alongside the Shuttle, they
will be helped into their parachute harness and CCA.

![](media/image19.png){width="1.6256944444444446in"
height="2.498611111111111in"}

Figure 15: A suit technician assists STS-112 astronaut Sandra Magnus to
suit up in the O&C Building. (http://nix.nasa.gov/)

![](media/image20.jpeg){width="3.0in" height="2.25in"}

Figure 16: Astronaut John Blaha is standing on the 195 foot level of the
FSS. The orbiter and its orange external fuel tank is visible in the
background, and the distance to the ground can be seen behind that.
(http://nix.nasa.gov/)

![](media/image21.png){width="3.75in" height="2.6006944444444446in"}

Figure 17: Astronaut Scott Horowitz being helped into his harness in the
White Room on the OAA. (http://nix.nasa.gov/)

They will then leave the "White Room" on the Orbiter Access Arm (OAA)
and enter the Shuttle middeck through the side hatch. The order for
ingress into the orbiter is by seating assignment, with flight deck
personnel (CDR, PLT, MS1, MS2) preceding the middeck personnel (MS3,
MS4, MS5).

The "closeout crew" help the astronauts into their seats, where the
parachutes are already positioned. The orbiter is currently in an
upright position in preparation for launch, so the crew lie on their
backs, on top of their parachutes. The support staff help the crew to
strap in, and the CDR and PLT then have additional steps to adjust their
headsets and controls. The support team assists with communication and
suit pressurization checks, then they leave, closing the Shuttle hatch
behind them.

![](media/image22.png){width="3.5006944444444446in" height="2.4625in"}

Figure 18: Astronaut Brent Jett is assisted by several members of the
Closeout Crew just before entering the Shuttle with them.
(http://nix.nasa.gov/)

Approximately one hour after a normal launch and successful achievement
of orbit, the mission specialists leave their seats, disconnect their
suits from the orbiter systems, configure the flight and middecks for
orbital operations, and lock the side hatch. Once the CDR and PLT have
finished their piloting duties (at about 90 minutes after launch), they
too leave their seats and then all crewmembers remove and stow their
ACES suits.

On landing day, the crew don their suits just before assuming their
seats for reentry. After landing, crewmembers will unstrap immediately
after wheel stop and wait for the support staff to open the side hatch
and enter the Shuttle. The convoy crew, accompanied by the flight
surgeon who is usually among the first ground crew personnel to enter
the Shuttle, then help the astronauts to exit the vehicle and remove
their suits.

**Contingency operations**

There are eight emergency egress modes for getting the crew out of the
Shuttle. The mode type depends upon the phase of flight during which the
emergency occurs, the nature of the emergency, and whether support staff
or rescue personnel are available to help the astronauts. In modes 1, 5,
and 8, the crew must exit the orbiter without assistance. In 2, 3, 4, 6,
and 7, ground personnel are present.

In all of the modes, certain basic assumptions are made. First, the crew
is expected to egress unaided as much as possible, even if rescue staff
are present. Next, it is assumed that the crew will help each other --
this may be particularly important if some of the crew are returning
from long duration missions, as when a Shuttle is ferrying home an ISS
crew. Those people who are authorized to declare an emergency and order
an egress are the crew commander, flight director, NASA test director
(NTD), and convoy commander.

**Prelaunch emergencies**

Mode 1 is an egress at the pad during the prelaunch period. In this
mode, the closeout crew have already left the launch platform, the side
hatch is closed, and the situation is too critical and/or unsafe to
dispatch rescue teams. The crew must therefore leave the orbiter
unaided.

![](media/image23.png){width="1.6256944444444446in"
height="2.498611111111111in"}

Figure 19: The Shuttle Endeavour at launch pad 39A.
(http://nix.nasa.gov/)

When an egress is called for by either the CDR or NTD, the OAA must be
repositioned[^4]. The crew unstrap themselves and leave their seats,
then open the side hatch and crawl out head first to the 195 foot level
of the FSS[^5]. They proceed in a "buddy system"[^6] to emergency
slidewire baskets which are located in recessed areas on the west side
of the FSS.

![](media/image24.jpeg){width="2.6666666666666665in"
height="2.0006944444444446in"}
![](media/image25.png){width="3.1256944444444446in"
height="2.0909722222222222in"}

Figure 20: Astronauts practice entering the slidewire baskets. Note the
difference between the suits worn STS-41D astronaut Judy Resnick in 1984
(left) and STS-105 crewmembers in 2001 (right). (http://nix.nasa.gov/)

Each of the seven baskets can hold up to three suited people and have
fire-resistant material around them to protect occupants. The baskets
are suspended from ¾ inch stainless steel cables by two trolleys, one of
which has an anti-rollback device. Once the crewmember and his or her
buddy are in the basket, they use a guillotine-like device to sever the
Kevlar rope which holds the basket in place. They then slide, in a
matter of seconds, to a ground level landing zone 1168 feet away from
the pad. The baskets are slowed by nets, then the south wall of the
basket can be released when a D-ring is pulled.

![](media/image26.jpeg){width="2.873611111111111in"
height="2.1569444444444446in"}
![](media/image27.png){width="2.873611111111111in"
height="1.9104166666666667in"}

Figure 21: At top left, the slide wire basket and net system, with the
distance from the launch pad clearly visible. At top right, a side view
of the STS-101 crewmembers show them learning how to exit the slidewire
baskets. (http://nix.nasa.gov/)

The crew then leave the basket and hurry to shelter within a concrete
bunker. Up to this point, the crew commander has been in charge; at the
bunker, however, the NTD is in command.

![](media/image28.png){width="3.332638888888889in"
height="2.2194444444444446in"}

Figure 22: While the flight crew speak with assembled reporters, the
protective bunker in which they can shelter is seen in the background.
The slidewire basket landing zone is off camera to the left, at the
astronauts' backs. (http://nix.nasa.gov/)

Depending upon the precise nature of the emergency, they may then leave
the area in an armored personnel carrier.[^7]

![](media/image29.png){width="2.7506944444444446in"
height="1.8388888888888888in"}![](media/image30.jpeg){width="2.7506944444444446in"
height="2.063888888888889in"}

Figure 23: At left, astronauts walk past the personnel carrier that will
take them from the protective bunker in the event of an emergency. At
right, astronauts sit in the M113 personnel carrier and take turns
driving it. (http://nix.nasa.gov/)

In Mode 2, another pad egress in the prelaunch period, the seven person
closeout crew is still present and the side hatch is still open, but (as
in Mode 1) the situation is too hazardous to dispatch additional rescue
personnel. When an egress of this type is ordered, the closeout crew
assists the astronauts out of the Shuttle and proceed into the baskets
and to the bunker with them.

![](media/image31.jpeg){width="3.0416666666666665in"
height="2.279861111111111in"}
![](media/image32.png){width="1.6256944444444446in"
height="2.498611111111111in"}

Figure 24: At left, astronauts and closeout crew practice evacuation
together. At right, STS-107 crewmembers Willie McCool (left) and Rick
Husband prepare to climb out of the basket, now that the side wall, with
its fire-protective covering, has been released. (http://nix.nasa.gov/)

In Mode 3, another pad egress in the prelaunch period, the closeout crew
has left and the side hatch is closed. However, in this case, a seven
person rescue team can be sent to the 195 foot level of the FSS to help
the astronauts. The crew still tries to get out of the Shuttle as best
they can on their own. If they cannot, then the rescue personnel will
open the side hatch and help them out. The astronauts and rescuers will
then leave the FSS, either by the slidewire baskets or the elevator, at
the discretion of the rescue team leader.

In a Mode 4, the closeout crew is still present, the side hatch is open,
and a rescue team can be sent in. The rescue personnel will then help
both closeout crew and astronauts to leave the Shuttle and all leave the
area together.

**Landing emergencies**

A Mode 5 scenario is an egress post-landing, with the astronauts
unassisted by ground personnel. The crew must leave the Shuttle through
the side hatch (opened or jettisoned) or window 8. A "hatch jettison
Mode 5" is used if there is imminent danger to the crew, such as fire or
collapsed landing gear. A "hatch on Mode 5" is appropriate when an
egress is not emergent but should be expedited, or if the landing has
occurred at a site without convoy crew support. Crew will descend to the
ground using the EESS (preferred) or "Sky Genie". If the side hatch
cannot be used, then the commander will declare a "window 8 Mode 5"
egress. If the Shuttle communications systems are not available after a
Mode 5, the crew can contact search and rescue forces using either their
survival radios or light signals.

![](media/image33.jpeg){width="2.7506944444444446in"
height="2.063888888888889in"}
![](media/image34.jpeg){width="2.873611111111111in"
height="2.1569444444444446in"}

Figure 25: Practicing for a Mode 5 with the EESS. (http://nix.nasa.gov/)

In a Mode 6 egress, the Shuttle has landed on or near the runway, and a
pre-positioned convoy crew is available to assist the astronauts. In a
Mode 7 scenario, the Shuttle has landed in a remote area, and the crew
are assisted by rescue personnel who arrive in helicopters.

**In-flight bailout**

A Mode 8 is an in-flight bailout. It can be over land or water, during
launch or reentry. The astronauts must leave the orbiter
[during]{.underline} [controlled, gliding flight at or below 30,000
feet]{.underline}. This is an important distinction, as it was not met
in either the Challenger or Columbia disasters. In neither of those was
the orbiter in controlled, gliding flight, so an in-flight bailout would
not have been possible (even if all the other requisite factors had been
present).

During a Mode 8, the commander will call for a bailout at 50,000 feet
and he or she will then place the Shuttle in a minimum sink rate
attitude and engage the autopilot. The crew will ready their suits. At
40,000 feet, CDR orders MS3 to vent the cabin via the pyro vent. MS3
will then monitor the cabin pressure via an altimeter while the rest of
the crew ready their D-rings and release their seat restraints. At
30,000 feet, CDR orders MS3 to jettison the side hatch via the T-handle.
The crew disconnect themselves from Shuttle communication and oxygen
systems. At 25,000 feet, MS3 leaves his or her seat and deploys the
escape pole. If, however, deconditioned crewmembers are on board, then
MS3 will help them while MS2 deploys the pole. The crew leave their
seats and move to the side hatch. The crew will then bail out, with
automatic opening of their parachutes. The main canopies should open
around 14,000 feet.

![](media/image35.jpeg){width="4.875in" height="3.6569444444444446in"}

Figure 26: Astronaut Frank Culbertson practices bailing out of the side
hatch. The escape pole is visible behind his shoulder.
(http://nix.nasa.gov/)

Rescue of the crew following a Mode 8 egress could take at least 8
hours, with available resources varying, depending upon location and
advance warning. The first rescuers are likely to be a C-130 with two
teams of 3 pararescue jumpers (PJs) and a motorized rescue boat. The
C-130 will also drop two 20-person life rafts in which the astronauts
and rescuers can await the helicopters.

![](media/image36.jpeg){width="5.375694444444444in"
height="4.031944444444444in"}

Figure 27: Practicing bailing out the life raft. Note that the older
LES, rather than the new ACES suit, is worn in this picture.
(http://nix.nasa.gov/)

In a case where a Mode 8 bailout is ordered shortly after launch (also
known as a "Contingency Abort"), the orbiter would be destroyed through
a self-destruct command as soon as the crew had evacuated.

**Aborted launch and emergency landing considerations**

In addition to the eight modes mentioned above, there are also aborted
launch scenarios. In a Return to Launch Site (RTLS), the orbiter
performs what Popular Mechanics calls a "terrifying somersault in the
sky". In this scenario, a major problem[^8] occurs within seconds of
launch and will prevent the Shuttle from safely reaching orbit. An RTLS
can be ordered within the first four minutes after liftoff and will
return the Shuttle to Kennedy Space Center within the next 30 minutes.
To execute an RTLS, the commander must, while flying at mach 6.5, flip
the Shuttle and its external fuel tank 180 degrees and glide back to a
landing at Kennedy Space Center. Astronaut John Young is quoted by
[Popular Mechanics]{.underline} as saying, "We have never done a powered
pitch-down separation at Mach 6.7, very rapidly. Theoretically it will
work, but practically will it work? ... I'd like to see us do away with
RTLS."

![](media/image37.jpeg){width="6.21875in" height="3.917361111111111in"}

Figure 28: An artist's rendition of an RTLS
(http://popularmechanics.com/science/space/2000/12/Astronauts_in_Danger/)

Adding to the challenge of flipping the Shuttle around at that speed is
the fact that the Shuttle will likely have a full payload bay during the
maneuver, since it will occur shortly after launch. If the orbiter
(which weighs about 500 tons) is carrying a heavy payload, like the ISS
lab module (30,000 lbs) or the Chandra observatory (13,000 lbs), then
its weight will be even higher and its center of gravity significantly
different from what the commander is used to maneuvering during normal
landings. Depending upon how large and massive the payload is, and how
well secured[^9], it is possible that it could even break free of its
restraints during landing and slide forward, perhaps damaging (or
crushing) the crew compartment. And, of course, the external fuel tank
will still be half full during the "flip".

The maneuver must be delayed until after the solid rocket boosters
(SRBs) have burned out and separated from the Shuttle at 2 minutes after
launch. Within 30 seconds of SRB separation, and while the main engines
are still firing, the commander initiates the RTLS. At first the Shuttle
will continue to fly away from Florida, at a steep pitch in order to
burn off fuel in the external tank. At an altitude of \~40 miles and a
speed of nearly Mach 7, the commander will perform a "pitch around", in
which the Shuttle's nose will be brought to point towards Florida, so
that the orbiter is now flying tail-first, with the engines firing. As
it flies through its own 5000^o^F exhaust, the Shuttle will slow.

![](media/image38.jpeg){width="5.207638888888889in"
height="4.082638888888889in"}

Figure 29: The RTLS maneuver cannot begin until after the solid-fuel
booster rockets burn out and separate. The RTLS is divided into the
steps shown in this diagram: It begins with the shuttle being put into a
steeper climb to burn off its load of liquid fuel. The pitch-around
maneuver turns the orbiter and fuel tank around. Thrust from the main
engines gradually cancels the shuttle's forward motion from Mach 7 to
zero. Main engines are then shut down. The external tank is jettisoned
and the shuttle enters a steep dive toward the landing site. The pilot
pulls the shuttle out of the dive. The shuttle enters a glide slope for
landing at the Kennedy Space Center.
(http://popularmechanics.com/science/space/2000/12/Astronauts_in_Danger/print.phtml)

As the Shuttle loses speed and altitude, the external tank is rapidly
emptied of fuel. When it is down to below 2% of its capacity, the
Shuttle can separate from it without its bouncing against the orbiter.
The tank falls into the ocean while the Shuttle (now much lighter) will
gain speed. Eventually, without additional fuel, the engines will shut
down and the Shuttle, now gliding in a steep dive, will approach
Florida. As they near the Space Center, the commander will pull out of
the dive and enter the normal glide slope for a routine landing.

Unfortunately, this maneuver has never been tested. John Young refused
to perform it during the first Shuttle flight, likening it to "Russian
roulette". Astronauts practice it in simulation, but as John Young says,
"The first person that does one will be able to tell you whether it
works or not." Fellow Shuttle commander Ken Cockrell agrees: "The first
crew to do it -- if it should ever happen, and hopefully it won't --
would be along for quite a ride."

Transoceanic Abort Landing (TAL) sites are used in the event a failure
develops too late for an RTLS to be used. Between 2 ½ and 8 ½ minutes
after launch, a TAL can be declared, and the orbiter would then follow a
trajectory across the Atlantic Ocean to a landing strip at one of four
potential landing sites: Ben Guerir Air Base in Morocco, Banjul
International Airport in Gambia, Zaragoza Air Base in Spain, or Moron
Air Base in Spain. Each of these sites has been equipped with
appropriate rescue devices for use with the Shuttle and are staffed with
NASA and/or DOD personnel during all launches and any contingency
landings. In a TAL site scenario, the
![](media/image39.jpeg){width="2.93125in"
height="3.7020833333333334in"}Shuttle will land within 45 minutes after
liftoff. The particular choice of TAL sites will depend upon the
orbiter's payload and planned orbital insertion inclination. [^10]

Figure 30: Stars indicate KSC and the TAL sites.
(http://www-pao.ksc.nasa.gov/kscpao/nasafact/tal.htm)

Although less risky than an RTLS, TAL landings remain challenging -- as
described above, landing a Shuttle immediately after liftoff, with a
full payload bay, can be significantly different than the normal
post-mission landings. On a brighter note, the astronauts will not have
suffered any microgravity-related deconditioning and will be in peak
physical shape to perform any physical activities after landing, such as
making an emergency egress (e.g. a Mode 5).

The SRB's and external tank will separate before landing, but the
Shuttle will have to be flown at an altitude of about 350,000 feet until
after main engine cut-off (MECO) and external tank separation. The
Shuttle will also have to perform a roll to maneuver to a heads up
position, and it will dump extra fuel to decrease weight and restore the
center of gravity to a more usual location.

At six minutes prior to TAL landing, its speed will be Mach 2.5 and its
altitude about 82,000 feet. One minute later, it will have decreased its
speed to Mach 1. A minute after that, the commander will take over
piloting control from the on-board computers and will execute a large
turn to align the Shuttle with the center of the runway; this maneuver
is called intercepting the Heading Alignment Circle (HAC) or "turning
the HAC". The maneuver decreases the speed still further and allows the
Shuttle to enter its final approach at 13,000 feet. At 1,800 feet
altitude (7,500 feet from the end of the runway), the commander performs
a pre-flare to change the glide slope from 19 degrees to 1.5 degrees.
Speed at touchdown is ideally \~300 knots per hour.

![](media/image40.jpeg){width="6.0in" height="3.9097222222222223in"}

Figure 31: A normal landing at Kennedy Space Center.
(http://nix.nasa.gov/)

If all has proceeded according to plan, a routine powerdown of the
orbiter, requiring 30 minutes, would take place before the crew exit the
vehicle -- unless an unsafe condition requires an emergency egress --
and, if all goes well, the crew are expected to board a C-130 for home
within 3 hours of landing at the TAL site.

In an "Abort Once Around" (AOA) or "Abort to Orbit" (ATO), a malfunction
has rendered the engines incapable of carrying the Shuttle to its
planned orbital altitude. As a result, in these abort situations, the
Shuttle will fly to a lower altitude, orbit the Earth once, and then
land. This orbit buys time for the ground control teams to study the
problem as well as to the allow the Shuttle to land at a primary landing
site (PLS) such as Edwards Air Force base.

![](media/image41.jpeg){width="5.123611111111111in"
height="3.563888888888889in"}

Figure 32: Just what we all hope for: a normal landing of the Shuttle!
(http://nix.nasa.gov/)

**References and Suggested Readings**

1\) DeHart, RL and Davis, JR. (Eds.). (2002). [Fundamentals of Aerospace
Medicine, 3^rd^ Edition.]{.underline} Philadelphia: Lippincott Williams
& Wilkins.

2\) Harding, R. (1989). [Survival in Space.]{.underline} London:
Routlege.

Office.

3\) "Crew Escapes", presentation given by Kira Bacal, MD, at UTMB
Aerospace Medicine Short Course, August 1999.

4\)
http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/sts_egress.html

5\) Coledan, S. "Astronauts in Danger", [Popular Mechanics]{.underline}
(2001),
http://popularmechanics.com/science/space/2000/12/Astronauts_in_Danger/

6\) [Time Magazine,]{.underline} "They Slipped the Surly Bonds of Earth
to Touch the Face of God," February 10, 1986, Time.Com, Space Newsfile,
http://www.time.com/time/reports/space/disaster3.html

7\) NASA Facts Online, "Space Shuttle Transoceanic Abort Landing (TAL)
Sites", http://www-pao.ksc.nasa.gov/kscpao/nasafact/tal.htm

8\) "Just in Case", NASA Explores, NASA Human Exploration and
Development of Space Enterprise, February 7, 2002,
http://media.nasaexplores.com/lessons/02-010/fullarticle.pdf

9\) Newkirk D. (1990). [Almanac of Soviet Manned Space
Flight.]{.underline} Houston: Gulf Publishing Company.

10\) Shayler DJ. (2000). [Disasters and Accidents in Manned
Spaceflight.]{.underline} Chichester: Springer-Praxis.

11\) Johnston SL, Smart KT, Arenare B, "Spaceflight Medical Transport
and Evacuation" in MR Barratt and SL Pool (Eds.). (in press).
[Principles of Clinical Medicine for Space Flight.]{.underline} New
York: Springer Verlag.

[^1]: Crew identifiers: Commander (CDR): red/A/Alpha; Pilot (PLT):
    yellow/B/Bravo; Mission Specialist 1 (MS1): blue/C/Charlie; MS2:
    green/D/Delta; MS3: orange/E/Echo; MS4 (or Payload Specialist (PS)
    1: brown/F/Foxtrot; MS5/PS2: purple/G/Golf

[^2]: Keep in mind that this window is not akin to a car window; the
    stresses upon it are considerable. For example, after a normal
    reentry, the external window temperature is \>200^o^F 4 minutes
    after landing, and remains above 130^o^F thirty minutes later.

[^3]: It can also be activated manually.

[^4]: The OAA is retracted from the Shuttle seven minutes before launch,
    but it can be put back in place in \~30 seconds.

[^5]: Remember, the orbiter is in its vertical launch position, which
    means that everything in the Shuttle is "on its side", making rapid
    movements difficult and creating numerous tripping hazards.

[^6]: "Buddies" are determined pre-flight.

[^7]: As part of their launch training, astronauts learn how to drive
    the APC and actually take it for a test spin at Kennedy Space
    Center.

[^8]: A "major problem" of this type would include an engine failure,
    cabin pressure loss, fuel leak, or compromised cooling system.

[^9]: Of course, most of these large payloads, like the lab module or
    satellites, are never intended to be landed in the Shuttle, as they
    are supposed to be left behind in orbit. As a result, concerns about
    their coming loose during landing are more than theoretical.

[^10]: Depending upon the mission, shuttles may launch with inclinations
    between 28.5 and 57 degrees. The lower inclination launches allow
    for heavier payloads.