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Ask The Mission Team - Question and Answer Session
Deborah Hahn, ISS Payload Processing Mission Manager
Deborah Hahn
ISS Payload Manager

Cooper from Rockledge: What is going up on STS-116? What is the importance of the P5?

Hahn: STS-116 is composed of three primary payloads: the P5 truss segment, the SPACEHAB single logistics module and the integrated cargo carrier with the service module debris panels and the DOD space transportation program deployable experiments. P5 will be used as a spacer, or bridge, between large solar arrays. It will also allow for reconfiguration of the power and cooling systems.

Daniel from Dallas, Texas: What is the SPACEHAB single module? What's in it? What is it for?

Hahn: The SPACEHAB logistics single module is a pressurized carrier. It provides approximately 1,100 cubic feet of volume for transportation of supplies, hardware and experiments to and from the International Space Station. Some of the hardware items stowed in the module on STS-116 for subsequent transfer to the space station are a video base ban signal processor, a rotary joint motor controller assembly, and an external TV camera group, and most importantly, some additional hardware of the oxygen generation system.

Jeremy from Tuscaloosa: What will the SPACEHAB module provide for the ISS?

Hahn: For STS-116, the SPACEHAB module will provide for the transfer of supplies, hardware and experiments to and from the International Space Station.

Justin from Tuscaloosa: When the payload is put into the cargo bay, what holds it down during launch? What happens if the payload gets damaged during liftoff?

Hahn: All the larger payloads installed in the orbiter payload bay are designed with trunnions which are held in the bay by latches that are configured on the orbiter for each specific payload. A lot of analysis is performed prior to each mission to ensure that payloads will be able to handle the stresses of the launch environment. Problems are rarely encountered. However, if problems do arise and they cannot be fixed on orbit, the payload will likely return with the orbiter, be repaired and flown on a later mission.

Nitin from Hyderabad: What is SPACEHAB? Why it is used in this mission?

Hahn: The SPACEHAB logistics single module is a pressurized carrier. It provides approximately 1,100 cubic feet of volume for transportation of supplies, hardware and experiments to and from the International Space Station. Some of the hardware items stowed in the module on STS-116 for subsequent transfer to the space station include a video base ban signal processor, a rotary joint motor controller assembly, an external TV camera group and an oxygen generation system.

Jennifer from Green Bay, WI: Will the SPACEHAB stay in space for bigger living/working quarters after all the cargo in it comes out or will it be sent back to earth for other upcoming missions?

Hahn: The SPACEHAB was not designed to become part of the International Space Station. Therefore, it is not removed from the orbiter payload bay during mission operations. The SPACEHAB serves as an extension of the volume of the orbiter. As a result, it returns with the orbiter in order to be used again to resupply the International Space Station for the STS-118 mission.

Robert Wennberg from Sweden: I'm curious as to the STS cargo capacity when landing. That is, could it take down Hubble when its service life has ended? Has the landing cargo capacity changed during the life of the space transportation system? Thank you.

Hahn: Back in 1979, the large space telescope, as HST was originally called, was planned to be returned to Earth for refurbishment and relaunch every five years. However, in 1985, contamination and structural loading concerns associated with the return to Earth aboard the space shuttle eliminated the concept of ground return from the program, and NASA decided instead that on-orbit servicing would be adequate to maintain the HST. The landing capacity of the shuttle has, in fact, been upgraded over time. In fact, on Discovery's last flight back in July, it was fitted with new wheels and tires that were designed to increase the shuttle's landing load capacity by 20 percent.

Michael from Herriman, UT: My two-part question is, I was wondering with the delay of the ISS assembly, are all of the major pieces of the station done at NASA or are there items still being built? And if so, which items are still pending delivery to NASA? Thanks.

Hahn: With the arrival at KSC of the European Space Agency's Columbus module earlier this year, all the major space station elements are now at Kennedy Space Center with the exception of Node 3. However, all these elements are still undergoing final assembly, testing and outfitting per their individual launch preparation schedules.

Francois from Namur (Belgium): Is the SPACEHAB module like the MPLM modules which are used to bring supplies to the ISS?

Hahn: The multi-purpose logistics module, MPLM, and the SPACEHAB perform a similar resupply function to the International Space Station. The MPLM is actually removed from the orbiter payload bay and attached to the station instead of staying in the payload bay, as SPACEHAB does.

Nitin from Hyderabad: Why is the payload installed at the launch pad? How is the payload installed in the orbiter cargo bay from the payload changeout room? How is the orbiter cargo bay opened for installation without exposing it to outside air and contaminants?

Hahn: Payloads can be installed in the space shuttle either horizontally at the Orbiter Processing Facility or vertically at the launch pad. There are a number of technical and operational considerations that drive the location of the installation for individual payloads. For example, since payloads installed at the launch pad do not have to be delivered until later in the processing flow, operational costs for the payload program can be reduced. Later delivery can also provide more time for payload owners who have limited life items with periodic refurbishment requirements included as part of the payload hardware.

After the space shuttle arrives at the launch pad, the rotating service structure is moved into place around the orbiter payload bay. The payload changeout room is the major feature of the rotating structure. Clean-air purges and specially designed seals help ensure that the payloads being transferred from the payload canister into the payload changeout room are not exposed to the open air.

Prior to the arrival of the space shuttle at the pad, the payload is delivered to the payload changeout room by the payload canister. The payload is transferred from the payload canister into the payload ground handling mechanism, which is a large handling fixture in the payload changeout room. Hooks configured on the payload ground handling mechanism hold the payload by the same trunnions that will hold the payload in the space shuttle.

When the transfer of the payload to the orbiter payload bay occurs, the payload ground handling mechanism translates forward along the floor of the payload changeout room and the load of the payload trunnions is transferred from the hooks on the payload ground handling mechanism to the payload retention latches on the orbiter payload bay.

Nitin from Hyderabad: What are Pico-satellites? I understand that three of them will be deployed during STS-116 mission. Where are they put in the cargo bay and how and when they are deployed?

Hahn: Pico-satellites are very tiny, coffee-cup-sized satellites. The three deployable pico-satellites are the atmospheric neutral density experiment, called ANDE, the radar fence transponder, called RAFT, and the micro-electro-mechanical system pico-satellite inspector, called MEPSI. They are installed on the integrated cargo carrier in bay 13 of the shuttle. While undocked from the International Space Station, RAFT and MEPSI are planned to be deployed on flight day 10, and ANDE will be deployed on flight day 12.

Nitin from Hyderabad: What is MAUI and RAMBO? How does it related to or affect payload?

Hahn: MAUI and RAMBO are two shuttle payloads of opportunity. The Maui Analysis of Upper-Atmospheric Injections, called MAUI, will use the Maui space surveillance site telescope system to observe selected space shuttle engine firings during nighttime over flight to validate plume calculations.

The RAM Burn Observations, called RAMBO payload, will measure infrared plumes from the shuttle orbiter maneuvering system engines to establish relevant inspection requirements.

Arthur from Sedona: Why does the ISS need a new electrical system and what will the new truss do?

Hahn: Well, it's not really a new electrical system. It's a reconfiguration of the power system from the space station early power configuration to the beginning of the final assembly complete power configuration. The successful addition of the P5 integrated truss segment is key to making all this happen. The overall configuration of the space station power system is quite complicated, and consists of power generation, energy storage, power management and power distribution equipment. I'd recommend that you read over the International Space Station electrical power system's electrical overview in the STS-116 press kit if you want more detailed information.

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