NASA’s rollercoaster escape for Ares I

by Chris Bergin

Looking like it would appear more at home at the nearby Disney attractions in Orlando, NASA is favouring a Rollercoaster Escape System for the Ares I pad.

The Emergency Egress Systems (EES) are currently going through trade studies at NASA, with the Rollercoaster option coming out on top – literally – in a September 27 presentation acquired by this site.

The full presentation from which this article was based is available for download on L2. Other associated L2 resources listed at the end of this article.

Currently, Shuttle launch pad complex 39B at the Kennedy Space Center (KSC) in Florida will be handed over to Constellation on April 1, 2007. The pad will undergo stages of major modification, firstly for the test flight of Ares I-1 – and subsequent test flights, and again for the first manned launch using Ares I.

The current slidewire basket system used for Shuttle crew and pad workers will be removed, with a new system installed into the taller pad configuration for the Ares program.

NASA is required to design the system ‘for a safe mode of emergency egress from the crew hatch of the CEV (Crew Exploration Vehicle/Orion) to a safe area for flight crew, closeout crew, contingency crew, and ground operations personnel while the CLV is at LC-39B.’

During the trade study, detailed analysis was performed on the following system elements: Ingress/egress routes for Pad flight and Ground Support Equipment (GSE) configurations. Operational tasks with associated manloading. Operations hazard levels and flight/closeout/contingency ground crew personnel emergency egress route criteria.

Previous studies for Shuttle and Apollo were used as guidelines, such as the Shuttle’s slidewire baskets to a bunker away from the pad, and Apollo’s high speed elevators to a blast room.

In total, four major concepts were put forward as Ares EES candidates: 1) Four to six separate four-man cab slide-wire systems to the safety bunker from the Fixed Service Structure (FSS) or Mobile Launcher (ML) tower. 2) Four separate four-to-six man car rail (rollercoaster) systems to the safety bunker from FSS or ML tower. 3) Elevator system to Pad Terminal Connection Room (PTCR) to blast room from FSS or ML tower. 4) Slide-tube system to safety bunker from FSS or ML tower.

The study defined the options as follows:

Slide-wire System:

‘A slide-wire system will be used from the crew access arm level of the ML tower or FSS to a bunker located on the west side of the pad. One basket will be attached to each slide wire and have a four person capacity.

‘This system will be start from the crew access arm level of the ML tower or FSS and terminate at a bunker located on the west side of the pad just outside of the perimeter fence.’

Rail Car (Rollercoaster) System:

‘An unpowered fixed single-rail system from the access arm level of the ML tower to the existing bunker would be used. The railcars could be enclosed to provide personnel protection. Each railcar can hold four to six people.

‘The rail would follow the ML tower vertically down to the pad surface, then turn and continue close to the ground to the safety bunker. A passive magnetic and friction braking system will decelerate the cars at the track’s end as well as prevent the cars from hitting each other.’

High Speed Elevator Alternative:

‘The egress route would be across the access arm, down the high-speed elevators, into the slide tube, and then into the existing blast room beneath the pad.’

Slidetude System:

‘A fixed slide tube made of either metal or hard plastic/fiberglass will extend from the access arm level of the ML tower or FSS to the existing bunker located on the west side of the pad.

‘The egress route will be across the access arm to the slide tube, down the slide tube to the bunker, and into the bunker. Each person would enter the tube one at a time from the crew access level on the tower and slide the distance to the bunker.’

The study listed its recommendations for the best EES option as the Rollercoaster/Rail Car system, despite it being the most expensive system – ranking it both first and second (from the RSS and the ML Tower), beating out the Slidewire, Elevators and Slidetube systems.

Further fine tuning and modifications to the designs are expected, with the Rollercoaster cars likely to be semi – or fully – enclosed, to protect escaping crew and/or workers from being sent into the path of an event, such as a hypergolic leak – which would be a serious issue if they weren’t enclosed in the cars.

Also relevant to the final design will be the call for a ‘clean pad’ – which would have impacts on such EES concepts.

The schedule calls for the fabrication of the design to start at the start of 2008, ready for installation into the pad in 2009.

Other L2 Resources For Ares I, V and Constellation: Ares I-1 Test Flight Plan (full outline) Presentation. ARES I Reference Trajectory. Boeing’s STS to Ares – Lessons Learned Presentation. Latest Ares I and Ares V baseline Configuration image and data. CLV DAC-1C (Changes to CLV Upper Stage).

Ares I-1: Four Seg+Dummy ‘Tuna Can’ stage. Ascent Developmental Flight Test Presentation. CLV Pad 39B Handover Info and Latest. New images of CLV on top of new MLP and LUT. Lockheed Martin CEV/Orion Updates. Constellation news updates. ATK figures on the 5-Seg Booster weight for CLV. 90 Minute Video of Constellation all hands meeting. CLV TIM Meeting Information. CLV/CaLV Infrastructure, Timelines and Information.

CEV-CLV Design Analysis Cycle Review (DAC-2) Presentation. Constellation SRR updates. CLV Stick – Troubleshooting/Alternatives/Updates. New CEV Images (include abort mode). Flight Design and Dynamics Division CEV update. CLV Mono-propellant RCS system. CEV pressurisation system review. CLV/CEV Configuration Images. The 2×3 Seg SRB Crew Launch Vehicle Option Presentation…plus more.

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