In the 1969 science fiction film Marooned, a trio of astronauts manning an experimental space station attempt to return to earth, only for their spacecraft’s main engine to fail. Without sufficient fuel either to initiate reentry or return to the space station, the astronauts find themselves – well, marooned – in orbit, doomed to slowly suffocate unless some bold rescue plan can be launched in time. Arguably every astronaut’s worst nightmare: to be stranded just within sight of home but no way to get there. In most science fiction stories, however, this scenario would easily be avoided by just having the crew hop into a convenient escape pod and fall back to earth a la C-3PO and R2-D2 in the opening of A New Hope. But how close are humans to creating real life escape pods for use in awesome space? Well, I’m glad you asked, because today we’re going to look at some of the coolest systems engineers have come up with in the past, such as one collapsable escape device should one find themselves stranded on the moon, and much more. So let’s free-fall into it all, shall we?

To begin with, the concept of a self-contained crew escape pod actually predates manned spaceflight. As military jets in the 1950s began flying ever faster and higher, engineers faced the problem of protecting pilots forced to bail out in such extreme conditions. This led to the development of a number of innovative escape systems. For example, crews of the Convair B-58 Hustler and North American XB-70 Valkyrie supersonic bombers sat in individual egg-shaped “Stanley Capsules” with sliding doors which, when activated, descended to seal them inside. Each capsule had its own independent oxygen supply, incorporated a small window, and enclosed the pilot and co-pilot’s control columns, allowing the aircraft to be flown even with the crew “buttoned up.” When the time came to eject, the capsules protected the crew from the effects of wind blast and frictional heating and automatically deployed parachutes to deliver them safely to the ground. The capsules were buoyant, allowing them to serve as life rafts, and contained survival kits, emergency beacons, and other rescue equipment. Bizarrely, when performing live tests of the Stanley Capsule, Convair engineers decided that the ideal test subject was not a monkey or chimpanzee but rather an anesthetized black bear. Pity the poor soul who had to open the capsule once it landed…

The General Dynamics F-111 Aardvark bomber, introduced in 1964, took this one step further by having the entire cockpit serve as an escape capsule, detaching and parachuting to earth with both crew members inside. By contrast, the fastest military aircraft ever built, the Mach 3-capable Lockheed SR-71 Blackbird spy plane, used ordinary ejection seats – Lockheed engineers having discovered that the crew’s regular pressure suits provided more than adequate protection against the forces of supersonic ejection.

As soon as the space age began, engineers began tackling the problem of allowing an astronaut to bail out of a stricken spacecraft. Compared to ejecting at supersonic speeds, however, the challenge was a daunting one. Not only did a prospective escape system have to protect the astronaut from the near vacuum of space, perform a deorbit burn, withstand the atmospheric reentry, and land safely on land or sea – but it also had to be light and compact enough to fit inside an already cramped spacecraft. Of the dozens of concepts proposed during the early 1960s, the two which came closest to actually being built back then were Douglas Aircraft’s Paracone and General Electric’s MOOSE.

The Paracone was designed as an orbital ejection seat for the Boeing X-20 Dyna-Soar – a winged spaceplane developed by the Air Force in the late 1950s for orbital reconnaissance and bombing missions. The device incorporated an oxygen supply, a solid-fuel retro-rocket, and a deployable shuttlecock-like ballute made of woven high-temperature Nickel alloy thread. After ejecting from the spacecraft, the astronaut would deploy the ballute and fire the retro-rocket to deorbit, the paracone’s large surface area keeping the reentry speed – and atmospheric heating – within survivable limits. Once in the atmosphere, the ballute also brought the astronaut’s terminal velocity down to only 42 kilometres per hour, eliminating the need for a separate parachute. On landing, the impact was cushioned by a crushable foam shock absorber.

General Electric’s MOOSE concept was even more radical. Originally standing for Man Out Of Space Easiest but later changed to the more official–sounding Manned Operations Orbital Safety Equipment, MOOSE consisted of a Polyethylene Terephthalate or PET plastic bag fitted with a flexible ablative heat shield. After zipping themselves into the bag, the space-suited astronaut would deploy a canister of expanding polyurethane foam, inflating the bag and heat shield into a blunt-ended cone shape and embedding themselves securely inside. This foam insulated the astronaut from the heat of reentry and provided shock-absorption on landing. The astronaut then oriented themselves using a handheld cold-gas thruster before firing a small solid-fuel retro-rocket to initiate reentry. If reentry was successful, a chest-mounted parachute would automatically deploy at a given altitude. MOOSE could land on both land and in water- the buoyant foam allowing it to double as a life raft – and included a radio beacon and a survival kit. Impressively, the whole system packed into a small bag weighing only 100 kilograms.

Scale models of MOOSE and samples of heat shield material were subjected to GE’s supersonic wind tunnel, while extensive foam inflation tests were conducted. The latter experiments revealed that it was necessary to add castor oil to the foam to allow the astronaut to extract themselves after landing. Testing culminated in dummies and test pilots being embedded in the MOOSE bag and dropped from a bridge in Valley Forge, Massachusetts. The results indicated that while likely harrowing to use, MOOSE could get an astronaut safely back to earth.

However, the Air Force cancelled the X-20 program in 1963, and the Mercury, Gemini, and Apollo capsules that carried the first American astronauts into space were too small for systems like Paracone and MOOSE. Mercury and Apollo instead used a Launch Escape Systems or LES, consisting of a solid fuel rocket mounted on a tower that would pull the capsule free of the booster in an emergency. Gemini, meanwhile, used fighter jet-style ejection seats. But these systems could only be used within a very narrow window of time and altitude after launch, and in most cases would have been useless. If the spacecraft reached orbit and its retro engines failed, the crew would be doomed.

But as the Apollo lunar landing program got underway, a requirement emerged for a different kind of escape system. Long-term plans for Apollo called for missions of ever-increasing duration, culminating in extended 20-day stays on the lunar surface. But such missions carried a significant risk, for after sitting dormant for 20 days the Lunar Module ascent engine might not start up, stranding the astronauts on the moon. NASA thus investigated various concepts for a lightweight vehicle to get the astronauts off the lunar surface in an emergency, known as the Lunar Escape System or LESS.

The LESS was based on a concept called the Lunar Flyer, developed by Bell Aircraft in 1965 to provide Apollo astronauts with enhanced mobility on the lunar surface. Effectively a stripped-down miniature Lunar Module, the Lunar Flyer consisted of a platform with a seat, landing legs and a small liquid-fuel rocket engine. While theoretically capable of carrying a single astronaut and 170kg of lunar rock samples over a range of up to 8km, the concept was ultimately abandoned in favour of the more conventional Lunar Roving Vehicle or “moon buggy” used by Apollos 15, 16, and 17.

The final design for LESS featured collapsible propellant tanks, allowing the whole device to be packed flat and stowed in one of the Lunar Module’s equipment bays. The vehicle could be deployed and assembled by a single astronaut in around an hour, with propellant being siphoned from the Lunar Module’s own tanks. However, weight and volume restrictions prevented the inclusion of a guidance computer, meaning the LESS would have to be flown manually. Using nothing but a simple 8-ball attitude indicator, a clock, and visual references such as the lunar horizon, the pilot would have to execute a series of timed attitude corrections during the ascent in order to place the LESS in roughly the same orbit as the Command-Service Module. Meanwhile, the Command Module pilot would use a radio and light beacon on the LESS to guide the CSM to a rendezvous. Once the LESS was secured to the CSM’s docking probe, the Command Module Pilot would don his spacesuit, depressurize the Command Module, and open the hatch. A successful rescue would require a combination of extraordinary piloting skills and a great deal of luck, especially as the astronauts would have only a few hours until their PLSS life-support backpacks ran out of oxygen.

As NASA’s budget was progressively slashed at the start of the 1970s, the planned long-duration Apollo missions were canceled – and with them went the need for systems like LESS. The first practical efforts to provide a means of space rescue would not come until the Skylab space station program in 1973. In the event of the crew’s Command-Service Module becoming disabled, a backup, CSM 119, was modified by replacing its storage lockers with two additional crew couches. The rescue craft would be flown by a crew of two, allowing the 3-man Skylab crew to be returned to earth. CSM 119 was rolled out to the launch pad only once, during the 1973 Skylab 3 mission. The crew CSM developed a problem with one of its reaction control system or RCS thruster quads, potentially preventing the crew from returning to earth. In the end, however, it was decided that the spacecraft could safely reenter with one failed quad, and the rescue mission was never launched. The rescue craft was kept on standby for the Skylab 4 mission, and later served as backup for the 1975 Apollo-Soyuz Test Project, whose objectives included testing universal docking hardware to allow US and Soviet spacecraft to rescue each other’s astronauts.

The development of the Space Transport System or Space Shuttle in the late 1970s presented an opportunity for NASA to develop new advanced crew escape systems, but due to the shuttle’s long and convoluted design process, little such hardware was actually fitted to the orbiters. The first four shuttle flights carried ejection seats for the Commander and Pilot, but these were later removed both to save weight and because subsequent missions carried additional crew members seated on the mid-deck, making ejection impossible.

Indeed, early shuttle crews blasted into orbit with surprisingly little safety equipment. They didn’t even wear pressure suits or parachutes – only lightweight flight suits, crash helmets, and Personal Egress Air Packs or PEAPSs that provided unpressurized fresh air in case the cabin filled with smoke or toxic fumes while still on the ground. This meant that in an emergency a shuttle crew had only two options: abort and attempt to land back at the launch site or 15 designated runways around the world, or ascend to orbit and immediately reenter the atmosphere. If the cabin depressurized or the orbiter became impossible to land safely, there was no chance of survival.

Provisions were made, however, for rescue in orbit by another shuttle. As the shuttles could not dock with each other and did not carry enough Extravehicular Mobility Units or EMUs for the entire crew, NASA developed the Personal Rescue Enclosure or PRE. This consisted of a 900 millimetre diameter fabric ball just large enough to hold a single crew member bent tucked in the fetal position. Once pressurized, the PRE would be carried by a space-suited astronaut from one shuttle to the other, with an oxygen mask and carbon dioxide scrubber keeping the occupant alive for up to an hour.

The Challenger disaster of January 28, 1986, prompted a major shift in shuttle operations and safety protocols. The PREs were scrapped, and all crew members were required to wear pressurized Launch Entry Suits – later updated to the Advanced Crew Escape Suit or ACES – during launch and reentry. Bailout capability was also added in the form of the Inflight Crew Escape System or ICES. In an emergency, the shuttle would be placed by autopilot into a stable glide, the entry hatch blown, and an inflatable pole deployed over the left wing. The crew members would then hook their harnesses to the pole and jump, allowing them to clear the wing before opening their parachutes. While a definite improvement, the system could only be used under very specific circumstances.

After damage to the thermal protection system caused the Space Shuttle Columbia to burn up on reentry on February 1, 2003, a program called Launch on Need was organized to provide rescue capability should another shuttle suffer similar damage. A backup shuttle would be fitted with extra seats and other provisions and kept on standby throughout the primary mission. A rescue mission would have seen the two shuttles rendezvous and lock onto each other with their remote manipulator arms, after which a rope-and-pulley system would be strung between the two airlocks, allowing an EMU suit to be transferred over. One by one the crew would don the suit and transfer to the rescue shuttle, the empty suit being returned each time. Once the crew had been transferred, the damaged shuttle would be commanded remotely to reenter and land automatically. Between 2005 and 2011, 12 Launch on Demand flights were prepared, but none were ever flown. In any case, except for the 2009 STS-125 mission to service the Hubble Space Telescope, all shuttle missions during this period were flown to the International Space Station, allowing the crew to return to earth via Russian Soyuz capsule if the orbiter became incapable of reentering safely.

Since the end of the Space Shuttle Program in 2011, the Soyuz became the de facto escape pod for the ISS, with at least one being docked to the station at all times. In more recent years it has been supplemented in this role by the SpaceX Dragon capsule. However, it remains to be seen whether future astronauts will be provided with a real-life equivalent to the dedicated sci-fi escape pod, allowing them to escape the nightmare scenario of being lost in space.

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