Weather Improving

SpaceX-3 on Launch Pad
Courtesy SpaceX

The Launch Weather Officer reports that conditions around Cape Canaveral improving this afternoon. The weather remains unstable, but all constraints have been cleared and the weather is expected to remain “go” through launch time. Officially, the forecast remains at a 40 percent chance of acceptable conditions for the 3:25 p.m. EDT launch time. NASA TV coverage will begin at 2:15 p.m. You can watch at

Launch Day Dawns in Florida

Space-3 on Launch PadGood morning from a cloudy Florida where SpaceX is preparing to launch its third operational mission to the International Space Station. The Falcon 9 rocket and Dragon spacecraft loaded with cargo have been rolled to the launch pad at Launch Complex 40 at Cape Canaveral Air Force Station and raised to its vertical launch position. Today’s launch time is 3:25 p.m. EDT with an instantaneous launch window to allow a link up with the International Space Station. The weather forecast still offers a 40 percent chance of acceptable conditions at launch time and meteorologists will spend the day surveying the skies for signs of thick clouds or other launch rule violations. NASA’s continuous coverage will begin on the Launch Blog and NASA TV at 2:15 p.m. In the meantime, we will report breaking news here as events warrant.

SpaceX Details Helium Leak

SpaceX released some of the details about the helium leak in the Falcon 9 rocket that scrubbed Monday’s launch attempt of the SpaceX cargo resupply mission to the International Space Station. Here is what the company said: “During Monday’s launch attempt, preflight checks detected that a helium valve in the stage separation pneumatic system was not holding the right pressure. This meant that the stage separation pistons would be reliant on a backup check valve. No issue was detected with the backup valve and a flight would likely have been successful, but SpaceX policy is not to launch with any known anomalies. We have brought the vehicle back to horizontal and are replacing the faulty valve, as well as inspecting the whole system for anything that may have contributed to the valve not working as designed.”

SpaceX-3 is slated for liftoff Friday at 3:25 p.m. EDT. Saturday was chosen as the backup day for launch with a launch time of 3:02 p.m. EDT.

SpaceX Selects Friday for Launch, Saturday Backup

The International Space Station Program and SpaceX have selected Friday, April 18 for the next launch attempt for the Falcon 9 rocket to send the Dragon cargo craft on the company’s third commercial resupply mission to the space station. Launch is scheduled for 3:25 p.m. EDT. The NASA Launch Blog and NASA TV coverage will begin at 2:15 p.m.

A launch on Friday results in a rendezvous with the space station on Sunday, April 20 and a grapple at 7:14 a.m. NASA TV coverage will begin at 5:45 a.m. with berthing coverage beginning at 9:30 a.m.

SpaceX has settled on a backup launch date of Saturday, April 19 for the best pair of launch dates for the science payloads being delivered to the station. If needed, a Saturday launch would occur at 3:02 p.m. This would be a three-day transit to the station instead of two days with grapple on Tuesday, April 22.

Forecast 40 Percent Go If Friday Launch Attempted

If NASA and SpaceX officials decide to attempt to launch SpaceX-3 to the International Space Station on Friday, there is a 40 percent chance of favorable weather. The Air Force 45th Weather Squadron issued its L-3 forecast, which predicts a chance of showers and thunderstorms that could result in violating the Thick Cloud, Lightning and Flight Through Precipitation rules.

Launch Day Dawns for SpaceX-3


Good morning from Kennedy Space Center in Florida! The sun has risen on launch day for the SpaceX-3 mission which remains on schedule for liftoff at 4:58 p.m. EDT from Cape Canaveral Air Force Station adjacent to Kennedy. The weather forecast calls for an 80 percent chance of acceptable conditions this afternoon at launch time. Meteorologists will be on the lookout for thick clouds that could develop as the day progresses. The Falcon 9 rocket and Dragon spacecraft were lifted into launch position yesterday, as seen in this picture from NASA TV. We’ll begin our continuous countdown coverage on the NASA Launch Blog at 3:45 p.m. NASA TV coverage begins at the same time here.

Mission Managers Give ‘Go’ for SpaceX-3 Launch

International Space Station Program officials, the international partners and representatives of SpaceX agreed Sunday to proceed with Monday’s scheduled launch of the SpaceX Falcon 9 rocket and its Dragon cargo craft on the company’s third commercial resupply mission to the orbital laboratory.

After a series of meetings and reviews of procedures, flight controllers, engineers and managers concluded that the SpaceX-3 mission could be conducted as planned without violating any launch commit criteria despite the loss Friday of a backup computer command relay box called a multiplexer/demultiplexer (MDM) that resides in the station’s S0 truss. The problem with the box, which measures 10.5 x 14.9 x 16.4 inches and weighs 50.8 pounds, occurred during a routine health check of the device. The prime multiplexer continues to operate normally. This pair of MDMs provide commanding to the station’s external cooling system, Solar Alpha Rotary joints, Mobile Transporter rail car and insight into other truss systems.

The engineering teams reported to mission managers that the station possesses enough redundancy to allow the SpaceX mission to launch Monday at 4:58 p.m. EDT from Launch Complex 40 at the Cape Canaveral Air Force Station, Fla. In advance of launch, the station’s Mobile Transporter will be moved to the proper position on the truss later today and after Dragon’s launch, the station’s solar arrays will be oriented Monday to the correct angles for the scheduled capture of the U.S. cargo craft on Wednesday and its berthing to the Earth-facing port on the Harmony module. These are steps that would properly configure the station for the mission even if the prime MDM experiences a problem.

Additionally, preparations are underway for a contingency spacewalk by two of the Expedition 39 crewmembers no earlier than around April 22 to replace the failed MDM with a spare housed inside the station. Mission managers approved a plan for the preparation of two of the U.S. spacesuits on the station and the replacement of a fan pump separator on one of the suits prior to the spacewalk. That work will begin immediately. The move of the Mobile Transporter rail car to another worksite from its current location will clear the area on the S0 truss for the spacewalking astronauts to gain access to the failed MDM during the planned excursion. The station crew will also be readying the spare MDM for its staging in the Quest airlock prior to the spacewalk.