Atlantis has gained one final mission, flying STS-135 to the International Space Station (ISS), with a launch date targeting June 28, 2011. Pending required funding allocation, Atlantis will carry a packed Multi-purpose Logistics Module (MPLM) and a Lightweight Multi-Purpose Carrier (LMC), on a 11+1+2 mission with a four person crew.
Atlantis has been – and will technically remain as – processing as the STS-335 LON (Launch On Need) mission in support of Endeavour’s STS-134 mission, officially manifested as the final mission for the Space Shuttle Program (SSP).
Calls to utilize the hardware for a real mission to the ISS resulted in evaluations into the optimum timing of such a flight, one which best supported the orbital outpost’s needs, whilst allowing for a mini-closure of the gap between the end of Shuttle and the opening CRS (Commercial Resupply Services) flights.
With the ASAP (Aerospace Safety Advisory Panel) noting their approval – both “informally and formally” – from a safety standpoint, the main assessment of STS-135′ safety was tasked to the NASA Engineering and Safety Center (NESC), per Senate refinements to the FY2011 budget proposal.
“The House authorization bill added the additional flight to mirror the Senate bill. There is some difference in how we would pay for it so everything isn’t locked down yet but we are continuing with the planning,” added one managerial overview on the latest Staff Senior Notes (L2).
“The Senate bill asked the NESC to do an independent assessment of the STS-135 flight from a safety perspective.”
STS-335/135 Specific Articles: http://www.nasaspaceflight.com/tag/sts-135/
The NESC safety assessment overview was presented to managers at the Johnson Space Center (JSC) on Friday, with pre-emption of STS-135 taking the next step seen via a note from SSP manager John Shannon.
“A CR (Change Request) will be put out (Friday) to slide the STS-335 launch date to June 28, 2011, which is consistent with what a STS-135 launch date would be,” noted Mr Shannon on the latest Shuttle/Standup/Integration report (L2). “It keeps us all on the same milestones for that.”
By Friday afternoon, notes of a meeting between SSP and ISS management confirmed the initiation of STS-135 as a “Real Planned Mission”, one which will go through the key Flight Definition and Requirements Directive (FDRD) process – the key baselining element for a mission.
The mission outline matches with previous evaluations of late, with a full 16 rack MPLM, and an LMC carrier that will be configured to accommodate the return of the failed External Thermal Control System (ETCS) Pump Module – to allow for evaluations on the ground into the root cause failure on the ISS.
A four person crew allows for the utilization of the Soyuz “LON” plan, which – in the highly unlikely event Atlantis was unable to return to Earth – would result in the STS-135 crewmembers returning on two Soyuz vehicles, staggered over their scheduled return dates, with Expedition crewmembers handing over their seats in return for an extended stay on the ISS.
The mission duration is being planned as 11+1+2, with one EVA – planned to be conducted by ISS crewmembers as a Stage EVA during the docked phase of the STS-135 mission – although Friday’s meeting spoke of a consideration in assigning one STS-135 crewmember for EVA tasks, to enhance the flexibility of the mission options.
At present, Soyuz TMA-22 is set to launch to the ISS in September, 2011 for an ISS crew rotation. Another Soyuz is set to launch in November, 2011 – which will be another installment of a new series of the veteran vehicle, designated Soyuz TMA-03M.
According to the meeting notes, crew selection will take place on September 14, with training – or crew loading – to begin on September 27. The June 28, 2011 launch date moves the mission four days to the right of previous evaluations.
Payload planning will continue throughout the coming weeks and months via meetings with ISS and Shuttle managers, who will work out the best utilization of Atlantis’ upmass, with notes referring to the potential addition of the Goddard Space Flight Center (GSFC) payload R2D2, and DTO (Detailed Test Objective) 703 STORRM (Sensor Test for Orion RelNav Risk Mitigation).
With Change Requests (CR) being added into the system, Atlantis will remain with a STS-335/135 call sign “for now” until the mission has been put through the baselining requirements – likely to be reviewed at upcoming Program Requirements Control Board (PRCB) meetings.
STS-135 “final” approval, from a manifest standpoint, will come at the political level via the required funding allocation in the NASA budget. With both the Senate and House refinements to the FY2011 budget proposal, the decision was technically passed back to NASA, and the safety assessments, which were undertaken – positively – on Friday.