MOD reviews special topics for Endeavour’s June mission to ISS

by Chris Gebhardt

With STS-125 safely completed, NASA is turning its attention towards the June 13 launch of Endeavour to the International Space Station. Particularly, the Mission Operations Directive (MOD) – which conducted their Flight Readiness Review (FRR) for STS-127 last week – paid special attention to “New Operations” that will be a part of Endeavour’s 16-day flight to complete assembly of the Kibo Japanese laboratory complex.

Launch Windows and Launch Opportunities:

Perhaps the most notable aspect of Endeavour’s launch campaign will be the short launch window available to the KSC launch team before a solar beta angle cutout begins on June 20.

a223This launch cutout period – designed to prevent Endeavour from being docked to the ISS when the beta angle exceeds 60 degrees (which will happen between July 3 and July 13) – extends from June 20 through July 12.

As such, this particular cutout provides NASA and the KSC launch team with only seven days of launch opportunities – which translates to five attempts in seven days based on PRSD pad hold time estimates.

“June 19 is last available launch day that can support nominal mission duration and maintain docked beta < 60 degrees,” notes the STS-127 MOD FRR overview document – one of 13 STS-127 FRR presentations available for download on L2.

However, the MOD FRR presentation notes that a launch on June 20 may be possible based on “atmospheric affects or timeline changes.”

Additionally, a launch after June 16 will result in a Passive Thermal Control requirement prior the Endeavour’s deorbit.

“If launch on or after 6/16, Passive Thermal Control may be required prior to deorbit,” notes the presentation.

A launch on June 13 – the opening of Endeavour’s window based on processing operations at launch pad 39-A – would see an opening of the day’s launch window at 7:12:08am.,with a preferred in-plane launch time of 7:17:08am.

After this, the launch window will advance by 23 to 26 minutes each day. This translates to day launch conditions for the first three days (3 days) of launch opportunities followed by four night launch opportunities.

However, despite the technical classification of STS-127’s last four June launch attempts as “night” launches, all on-orbit photography of the External Tank (ET) will occur under daylight conditions, enabling the Flight Crew to obtain hand-held imagery of the ET after separation.

As has been seen on previous missions to the ISS, Endeavour’s launch will be targeted for a FD-3 (Flight Day 3) rendezvous with the ISS. Nevertheless, starting with the second launch attempt, Endeavour will have the capability to rendezvous with the ISS on FD-4 should a glitch keep Endeavour on the launch pad for an additional few minutes.

Though it remains to be seen whether or not the Mission Management Team (MMT) will approve an FD-4 rendezvous given the mission’s long duration of 16+0+2 flight days, the on-orbit phasing angles between Endeavour and the ISS will permit a FD-4 rendezvous for a June 14, 16, or 18 launch.

For the duration of the launch window, Endeavour’s in-plane launch times are: June 13 at 7:17:08am.; June 14 at 6:51:26am.; June 15 at 6:28:54am.; June 16 at 6:03:12am.; June 17 at 5:40:41am.; June 18 at 5:14:59am.; June 19 at 4:52:27am.; and June 20: 4:31:45am.

New Operations:

a317One of the new operations that will be performed during STS-127 relates to the berthing of the Japanese Exposed Facility (JEF) to the Japanese Pressurize Module (JPM).

“Berthing occurs using the SSRMS (Space Station Remote Manipulator System) and mating to a one-of-a-kind JAXA mechanism, the Exposed Facility Berthing Mechanism (EFBM),” notes the MOD presentation.

The complication with this procedure is that all of the command interfaces for the EFBM are zero fault tolerant. However, the MOD notes that a backup berthing method is available should the EFBM fail. This backup method would involve berthing the JEF manually using an EV crew.

If this were to become necessary, mission timelines indicate that berthing of the JEF would be deferred to EVA-2 from its original timelined berthing during EVA-1.

Furthermore, the berthing operation of the JEF holds the potential to prolong EVA-1 to an elapsed time of 7-hours 30-minutes – though this is highly reliant upon LiOH (Lithium Hydroxide – or Carbon Dioxide scrubber) availability post STS-125.

Moreover, based on this analysis, JAXA (Japanese Aerospace and Exploration Agency) agree to build contingency power and data cables for the EFBM. Those cables are manifested on STS-127 should the Flight Crew require them during EVA-1 or 2.

The MOD also notes that operations to transfer payloads from the JLE (Japanese Experiment Logistics Module Exposed Section) to the JEF will be accomplished by the JEM RMS (Japanese Experiment Module Remote Manipulator System).

a510In all, the JEM RMS will be responsible for transferring three JAXA payloads to the JEF: MAXI, ICS-EF, and SEDA-AP. This is the first loaded operation of the JEM RMS, a component that was launched to the ISS on the STS-124 flight last June. However, there are concerns regarding the operation of the JEM RMS.

“Several components of the JEM RMS and the mechanical joints of the JEM RMS are zero fault tolerant,” notes the MOD FRR.

In the event of a JEM RMS failure, a back-up drive system can be used; however, this back-up drive system will add significant time to the task at hand. Furthermore, to mitigate any failures of the JEM RMS that may result from operator error, the on-orbit station crew and JAXA controllers have practiced the necessary sequence of RMS maneuvers on-orbit.

Also noted by the MOD is the fact that STS-127 will be the first shuttle mission to visit an ISS crewed by six people. This will result in 13 people occupying the ISS and its various workstations and modules during the mission.

“Thirteen crewmembers on ISS,” notes the MOD FRR presentation. “Most significant change is waste management. Original plan was 6 Shuttle crewmembers using the ISS WHC to minimize liquid waste in Shuttle toilet.”

The amount of liquid waste in the shuttle’s waste tanks must be limited from FD-4 through undocking because the standard waste dumps will be unavailable after JEF berthing during EVA-1.

a48The next new operation discussed by the MOD during their FRR pertained to the R&R (Removal and Replacement) of six P6 batteries.

The battery R&R activities are baselined for EVAs 3 and 4 and will involve moving the SSRMS by way of the Mobile Transporter (MT) from WS7 (Work Station 7) to WS8.

Furthermore, this translation of the SSRMS on the MT will occur with the ICC-VLD (Integrated Cargo Carrier – Vertical Lightweight Deployable) firmly fastened to the end of the SSRMS.

This operation is necessary as the six new P6 batteries will be stored on the ICC-VLD for launch. Likewise, the six old P6 batteries will be attached to the ICC-VLD for the return trip to Earth.

Further complicating the battery R&R is the necessity for the Port SARJ (Solar Alpha Rotary Joint) to rotate with the MT at WS8 during non-EVA activities while remaining “parked” during the actual R&R operations as the SSRMS’s reach will extend beyond the SARJ interface.

More so, power channel 2B will be taken offline after EVA-1 on FD-4 and reactivated on FD-11, one day after the battery R&R is scheduled to be completed.

Finally, after Endeavour undocks from the station, her crew will be tasked with deploying four small satellites from the payload bay.

The first satellites to be deployed will be the DRAGON SATs (Dual RF Autonomous GPS On-Orbit Navigator Satellites). These two picosats will undergo a retrograde deploy, separating from each other via a spring assembly after they leave their protective canister in Endeavour’s payload bay.

Endeavour – which will have her OBSS MPMs “rolled-out” – will not have to perform a separation maneuver after deploying these satellites, which are designed to study autonomous rendezvous and docking and GPS technology.

Furthermore, Endeavour’s crew will also deploy two micro-satellites which are dubbed ANDE (Atmospheric Neutral Density Experiment) – ANDE Active and ANDE Passive to be precise.

The two satellites will be deployed from Endeavour’s payload bay via the Internal Cargo Unit (ICU) which will house the satellites during Endeavour’s docked mission. The satellites are designed to separate from the ICU 27-seconds after leaving Endeavour and study atmospheric density and composition.

As with the DRAGON SAT deploy, ANDE will be deployed using a retrograde deploy operation and the OBSS MPMs will be “rolled-out.” However, unlike DRAGON SAT, Endeavour will have to perform a separation burn after deploying ANDE.

L2 members: Documentation – from which most of the above article has quoted snippets – is available in full in the related L2 sections, now over 4000 gbs in size

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