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ISS News & Mission: STS-104 (ISS-7A Airlock) Development Events of the Airlock

Mission Overview

The Crew: Commander: Steven W. Lindsey Pilot: Charles O. Hobaugh Mission Specialist: Michael L. Gernhard Mission Specialist: Janet L. Kavandi Mission Specialist: James F. Reilly

Atlantis approaches the ISS to before docking, the US lab is at right

Major Mission Goals: Airlock removal by SSRMS and docking to Node-1 Install 2 sets of 2 air tanks to the airlock Test of station EVA pre-breath procedure First use of Airlock for an EVA 3 hours orbital reboost Delivery of parts & supplies including a replacement SM treadmill chassis

STS-104 Brief Mission Plan The STS-104/7A mission was to deliver the US Airlock named 'Quest' to the ISS. Failures of the ISS computers and SSRMS caused delays in the 7A mission. The delays even threatened to delay the 7A mission until after 7A.1 which is more importantly to return the ISS-2 crew. After the failures were well understood and contingencies developed the 7A flight was rescheduled for July 12 with 7A.1 for the first week in August. If launch is delayed to some point, 7A.1 will take a higher priority, fly as scheduled to replace the ISS-2 crew, and 7A would fly in September. After a scheduled launch on July 12, the shuttle Atlantis (OV-104) will dock to the ISS on flight day 3. FD 1 - Launch FD 2 - EVA and Rendezvous preparations FD 3 - Docking & hatch opening, crews meet and conference reviewing EVA and Airlock installation plans FD 4 - Airlock Installation EVA#1. After EVA, the shuttle-station hatches will be opened again and the shuttle crew will aid in activation of the airlock and connecting it to station systems FD 5 - EVA #2 Prep, Airlock preparations & outfitting. FD 6 - EVA #2 preparations FD 7 - EVA #2 Install 2 air tanks. FD 8 - Off duty time & EVA #3 preparations FD 9 - EVA #3 Install 2 air tanks FD 10 - Undocking FD 11 - Landing Preparations FD 12 - Landing The Airlock For a detailed development events list for the US Airlock, see US Airlock Development. The Airlock is to provide the ISS with a robust EVA facility to replace the Russian Service Module docking node airlock facility (which only interfaces with Russian Orlan suits). The US airlock serves both shuttle EMU space suits, and Russian Orlan suits. Using the Russian airlock is risky if for some reason it can't be repressurized, as it would divide the station in two. Just using it causes disruptions in air flow between modules and communications and control lines that have to be disconnected to its close hatches. It also has more limited air replenishment tanks (those carried onboard some Progress resupply flights), and very limited space for tools and equipment. To improve the situation on the Russian side, a docking compartment and airlock will be attached to the Service Module later in 2001, however it will be a much smaller and limited airlock than the US Airlock. These factors make EVA's from the Russian segment of the station very undesirable and disruptive to routine station operations, hence all ISS EVA's (except for a minor Service Module hatch movement) have been done from docked space shuttles. With the addition of the US Airlock, ISS crews can now perform maintenance EVA's, station construction, and shuttle assembly missions can use the station airlock instead of the shuttles, reducing interruptions in shuttle docked operations (the shuttle airlock use blocks the shuttle-station docking port) The airlock consists of a large pressurized module for space suit storage, servicing tools and EVA tools, and a smaller airlock module similar to the space shuttle airlock, capable of holding 2 astronauts and some equipment. The outside of the airlock is used to attach air tanks to replenish what's lost when the airlock is depressurized to space (air is not reclaimed when depressurizing), and tool boxes. The air tanks can be replaced periodically by shuttle servicing missions. The airlock contains: Avionics rack including 3 communications panels for wired microphones, or EVA spacesuit radio repeaters to pass signals from the suits radios to the station radio system. Another rack in the equipment space provides the ability to regenerate space suit carbon dioxide filters, using high temperatures to bake carbon dioxide out of spacesuit filters enabling them to absorb carbon dioxide again on another EVA. Previously all filters were returned to Earth once they were used up and fresh ones replaced in suits. Along with the airlock, 2 sets of 2 tanks (oxygen and nitrogen) will be attached to the Airlock once its installed to be used to pressurize the airlock, the station when needed, and supply experiments in the US segment modules. After 3 days of assembly, the airlock is fully operational and will be used for the third EVA of the shuttle assembly mission. Major Mission Contingency Plans If the shuttle can't dock to the station or the mission is aborted for some reason, the Airlock can be left in the cargo bay and the Airlock returned to Earth. That can be done by reducing OMS propellant weight in the aft OMS pods to allow for proper weight and balance of the shuttle to fly and land normally. The worst case failure reasonably imaginable is if all 3 hard drives failed in the 3 Command and Control computers (MDM's) on the US segment which control the SSRMS before lifting the Airlock out of the shuttle cargo bay mounts. In this position the airlock would have to be returned to Earth. As long as the airlock has been pulled about 6 inches out of the shuttle cargo bay, by that point, the arm's C&C's would contain all data needed to move the airlock from the shuttle to within 3 feet from Node-1 where it can be connected to power to heat it's systems from freezing. After that, the airlock could remain for a long period while problems were solved although it could not be used in any other way. If the module were to be left near the Node docking port, the module could be docked the next day without astronauts to do an additional EVA unless the space vision system were to fail. Astronauts will rig a shuttle tether line to the power cable to insure the power cable they install will not fowl the docking port as the Airlock is moved to mate with Node-1. Detailed Flight Day Descriptions FD 1 - Launch FD 2 - EVA and Rendezvous preparations FD 3 - After docking, the station hatch will be opened and the crews will greet each other and discuss assembly operations planned for the mission. FD 4 - Airlock Installation EVA#1, Spacewalkers: Michael Gernhardt, James Reilly, Estimated Time: 6 hours, 45 minutes. The astronauts will assist SSRMS operator Susan Helms with the installation of the Joint Airlock onto the station. The Shuttle RMS can't place the airlock into the right location for docking, so the grapple fixture was located in a position ideal for the SSRMS to reach, and the shuttle RMS can't even reach the grapple point to lift the airlock at all. The first major tasks for the space walkers will be to remove an insulating cover from the airlock's Common Berthing Mechanism and remove protective covers from the berthing mechanism's seals while the airlock is still inside Atlantis' payload bay. The ISS crew will cycle open the Node-1 hatch mechanism, astronauts during EVA will release pins allowing the hatch to open without getting jammed by parts of an antenna connector which fell apart during an EVA on the 6A mission while removing the early comm antenna mounted on the hatch. They will install high-pressure gas tank attachment points, thermal covers onto the airlock, and seals will be removed. Then, they will disconnect a power cable from the airlock which maintains the temperature above freezing for critical system in the Airlock like water lines. Helms will lift the airlock out of Atlantis' payload bay as the two space walkers wait inside the shuttle's airlock for about 2.5 hours while the module is moved to near Node-1. When the Joint Airlock is near its attachment point on the station, Gernhardt and Reilly will leave the airlock again and inspect the docking mechanism and provide any assistance in the berthing process if needed, but this is not required unless the space vision system were to fail leaving Helm's guideless to position the Airlock properly. Once the airlock is attached, they will drive bolts in the CBM to firmly attach the Airlock and Gernhardt will connect a power cable to it. There is 4 hours margin to in the schedule to get power reapplied to the module which can be without power heating for 6-10 hours (power must be applied by EVA connectors, or interior connectors or interior waterlines to flow warm station water in the module lines to prevent freezing). Actually EVA spacesuit time would be the most constraining factor in timing in the event of problems during the install of the module. Airlock heaters will be powered from the ISS, they will close the hatches for further leak checks during the crew sleep period. After EVA, the shuttle-station hatches will be opened again and the shuttle crew will aid in activation of the airlock and connecting it to station systems. FD 5 - EVA #2 Prep, Airlock preparations & outfitting. Electrical, O and N lines and water lines will be connected between the Node and the Airlock. The shuttle will be used to pressurize the N and O lines, vents will be installed in the Airlock, and the lines will be purged of any contaminants into the station's air. Setup winds down, close hatches, and leak checks FD 6 - EVA #2 preparations. Hatch will be removed from the equipment lock and attached to the crew lock space, Helm's spacesuit will be installed in the airlock and attached to systems to prove the airlock can support the suit in power, communications, etc. A new pre-breath procedure will be demonstrated. Oxygen masks will be used for 2 hours and 20 minutes and the crew will use hoses to move back to the Lab where they exercise on the bycycle ergometer for 10 minutes to inprove their absorbtion of oxygen and flushing of the nitrogen from their bodies improving adaptation to 100% oxygen. After that, they will return to the airlock, reduce its pressure to 10.2 PSI, and begin donning their spacesuits and prebreathing 100% oxygen again in their suits. The new procedure was required by the inability to easily reduce the station's air pressure as was done on the shuttle. The station was designed for sea level pressure for experiments and equipment (like off the shelf laptops and other electronic equipment). The airlock can be depressurized to 10.2 by forcing air into the station, but after that the air in the crewlock is the only air lost overboard when reducing to vacuum. This procedure replaced a earlier idea of having the EVA crew 'camp out' in the equipment lock overnight before a EVA, isolated from the rest of the station, and with an air pressure barrier between modules which would slow any emergency hatch opening. FD 7 - EVA #2 Install 2 air tanks. Astronauts Michael Gernhardt, James Reilly, Estimated Time: 5 hours, 30 minutes. Installation of the first set of 2 High-Pressure Gas Tanks - one oxygen tank and one nitrogen tank - onto the Joint Airlock. Gernhardt will release the latches holding the first tank in the payload bay to allow the SSRMS, to lift the tanks up to the airlock. The shuttle RMS could not place the tanks in the right area of the airlock to make it possible for the astronauts to man handle the tanks into proper position, but the tanks can be lifted by the RMS although no contingency is envisioned where this would be needed. Meanwhile, Reilly will be installing foot platforms and handrails on the airlock. Then, Reilly and Gernhardt will take the tank as Helms releases it from the arm next to their mounting points. Astronauts will then guide the tank onto a guide post sticking out from the airlock, serving to eliminate rotational motion and keeping it in position to attach to its mounting points, and attach the tanks to the airlock. They will attach it to the airlock and then connect cables from the airlock to the tank. The process will start over again for the installation of the second tank. As Reilly is connecting the cables between the airlock and second tank, Gernhardt will place insulating covers on several airlock fixtures. If arm failures were to prevent the attachment of the air tanks, they would be reflown on a later mission. The shuttle RMS can't reach the mounting location for these tanks. FD 8 - OFF duty time & EVA #3 preperations. The 2 shuttle spacesuits will be installed in the airlock in preperations for the next days , tools removed from the airlock, SAFER checkout. FD 9 - EVA #3 Install 2 air tanks. Astronauts Michael Gernhardt, James Reilly, Estimated Time: 5 hours, 30 minutes. The third space walk will be the first based out of the space station's new Joint Airlock using the new 2 hour pre-breath procedure. The major objective of the mission's third space walk is to install the second set of High-Pressure Gas Tanks. The steps to complete this task will mirror the steps taken during the mission's second space walk. Also, a cable will be attached to the airlock that will allow communications with Russian space suits, installation of handholds on the airlock will be done and install thermal covers on the exterior gas tanks' grapple fixtures, and a cable stowed that was used on the 5A mission.. If arm failures were to prevent the attachment of the air tanks, they would be reflown on a later mission. FD 10 - Undocking, shuttle does a 1 orbit fly around FD 11 - Landing Preperations FD 12 - Landing In addition to the Airlock, the shuttle will carry a limited amount of supplies to the station crew including parts for the broken treadmill, and small personal items for the ISS crew. The shuttle will be returning 2 failed hard drives from US segment C&C computers (MDM's) for analysis of failures during the 6A assembly mission. After the shuttle departs, the ISS-2 crew will begin to prepare for handover the the new ISS crew to be launched n 7A.1 in August. They will pack, write up procedures and notes about operatinfg the station in its current form. They will clean up the station and prepare storage spaces for the supplies to be carried on 7A.1's MPLM resupply module.

Other Station News The 7A assembly flight completes the Space Station Phase 2 project. Phase 1 was the NASA-Mir program with Russia. Phase 2 was the initial assembly of the ISS to a 3 man permanently manned facility. Phase 3 begins later in 2001 with the assembly of more elements to support up to 7 people permanently. The Service Module treadmill is broken and only used in unpowered 'feathered' mode until replaced by new parts to be delivered on the next couple of missions. S0, S1, P1 truss segments are undergoing integration tests in the Space Station Processing Facility at KSC. Some problems with the Ammonia thermal control systems which require more testing in the future. S6 truss is not yet delivered. The ISS-2 crew now has the ability to make phone calls and receive phone calls from NASA authorized persons. Processes for the flight of tourists and other non-astronauts are being developed. On June 22 a training plan for flight to the ISS for non-astronauts was completed between the international partners. On overall policy for the commercialization of the station is still under development by NASA Headquarters, and tourist flight will be delayed until this overall policy is adopted. Bush administration budget cuts in the station project are still causing negotiations among the international partners and NASA over how to complete the station to 7 person capacity. So far, only the Italian space agency is in serious talks to supply the US with the Habitation module relieving the USA from the cost of continued development of the US Hab module. A decision about manufacture of a Hab module can wait until 2003 according to ISS program manger Tommy Holloway (6/25/01).

Station and Shuttle robotic arms carefully move astronauts and modules around the station in coordination

The US Airlock module in launch configuration at the ISS assembly building at the Kennedy Space Center

The Airlock being moved from the shuttle to its docking port on Node-1

The interior of the Airlock module - airlock compartment. The outer hatch in on the far end bottom, and the space suit services panel is visible next to the hatch.

STS-104 Shuttle Cargo Bay Payloads: Station Joint Airlock - The Joint Airlock is a pressurized flight element consisting of two cylindrical chambers attached end-to-end by a connecting bulkhead and hatch. Once installed and activated, the Airlock becomes the primary path for International Space Station space walk entry and departure for US spacesuits, which are known as Extravehicular Mobility Units, or EMUs. In addition, the Joint Airlock is designed to support the Russian Orlan spacesuit for EVA activity. The Joint Airlock acts as a stowage area for EMU hardware as well as a staging area for crew members preparing to conduct a space walk. A combination of the Russian depress pump and pressure equalization valves located within the hatches accommodate the depressurization /pressurization capability of the Airlock. The addition of the Airlock permits space station-based space walks to be performed without major loss of environmental consumables such as air. High Pressure Gas Tanks (HPGT) - Two oxygen and two nitrogen High Pressure Gas Tanks are attached externally to the Airlock and will be transported to the space station attached to a Space Lab Double Pallet in the orbiter's cargo bay. These tanks provide a replenishable source of gas to the Atmosphere Control and Supply System and 900 psi oxygen for recharging the EMUs. Recharging the high pressure tanks is accomplished by the orbiter when it is docked to the station's Pressurized Mating Adapter 2 or Pressurized Mating Adapter 3, using lines that are routed through the pressurized elements. The Oxygen Recharge Compressor Assembly is used to pump oxygen from the shuttle tanks into the high-pressure oxygen tanks on the space station. IMAX Cargo Bay Camera-3D - The IMAX Cargo Bay Camera-3D payload is a 65 mm color 3-D motion picture camera system. The system consists of a camera, a lens turret assembly, and a film magazine containing approximately 1,646 meters (5,400 feet) of film. The camera system is housed in an insulated pressurized enclosure with a movable lens window cover, and is mounted in the cargo bay on a Get-Away Special beam. The camera system is operated from the Aft Flight Deck with a Payload and General Support Computer. The dc power for heating and camera operation will be supplied by the orbiter. An audio recorder with microphones supplied by the customer will be used in the crew compartment in conjunction with the camera system. In-cabin Payloads: EarthKAM- EarthKAM is a NASA-sponsored program that enables middle school students to take photographs of the Earth from a camera aboard the space shuttle. During missions, students work collectively and use interactive Web pages to target images and investigate the Earth from the unique perspective of space. SIMPLEX - Shuttle Ionospheric Modification with Pulsed Local Exhaust The objective of the SIMPLEX activity is to determine the source of Very High Frequency radar echoes caused by the orbiter and its Orbiter Maneuvering System, OMS, engine firings. The principal investigator will use the collected data to examine the effects of orbital kinetic energy on ionospheric irregularities and to understand the processes that take place with the venting of exhaust materials. SIMPLEX sensors may collect data during any encounter opportunity when the orbiter support activities meet the criteria defined. SIMPLEX requires 20 cooperative tests of orbiter thruster firings on multiple flights. The SIMPLEX payload has no flight hardware; Orbiter OMS thruster firings will be used to create ionospheric disturbances for observation by the SIMPLEX radars.

Mission Results All went well with the mission untils after installation of the Airlock when two minor problems cropped up requiring time to troubleshoot the issues resulting in a extension of the mission one day. This allowed the crews to slow their work and adjust to the problems. The two issues were minor, first when activating the newly attached Airlock, about half a liter of water leaked into the station from the modules plumbing due to air trapped in the pipes whne they were connected. This caused the stations caution and warning system to sound an alarm falsely indicating a failure of the stations cooling system. The astronauts soaked up the water and let the ground control team sort out what had happened. There was no serious issue other than cleaning up the excess water. The second problem was more serious although totally correctable. One of two air valves (a primary and a backup) seperating the Airlock from Node-1 leaked slightly. The computer controlled valves are used for controlling flow of forced air between the modules, like a homes central heating and cooling ducts. Since the Airlock must be depressurized for EVA's to 10.2 psi, the valves must close completely of air from Node-1 would leak into the Airlock. ISS commander Yuri Usachev said it looked like the valve was being over drived by its motor past the full closed position when the computer commanded it to close. Replacement of the valve with an on-board spare would take a few hours to complete and given the STS-104's short mission, already 12 hours behind schedule it was decided to seal off the air duct and replace the valve later. During EVA 2, astrounats transferred 3 air tanks instead of just 2 planned before flight. After the shuttle departed and prepared for landing, weather at the Kennedy Space Center threatened the landing site with rain at about the scheduld time of the shuttle landing, rain was approaching from the southwest, but still far away at the time mission controllers had to decide to deorbit the shuttle. Given that chance that rain could reach KSC before the shuttle did, landing was delayed a day. When the shuttle deorbited the next day, it flew across Central America and Mexico in darkness, prompting people to call authorities claiming seeing stange lights in the sky, and boom's. In some cases, searches were conducted for crashed planes, but in the end it was only the shuttle passing overhead and its sonic booms starteling unsuspecting people.

The Airlock ground trainer setup similar to the on orbit configuration. Below, the Airlock on-orbit

The shuttle and station crews review procedures before the first EVA

Above, the SSRMS takes a air tank from the shuttle, Below it places a tank on the Airlock

Late in the flight, Node-1 is filled with containers of supplies and items for return to Earth

A complete guide to the Soviet manned space program from 1960 to 1990 Details & Order information

Sample of Chapter 5

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